Sweet corn hybrid named HMX59BS604

ABSTRACT

A novel sweet corn hybrid plant, designated HMX59BS604 is disclosed. The invention relates to the seeds of sweet corn hybrid HMX59BS604, to the plants and plant parts of sweet corn hybrid HMX59BS604, and to methods for producing a sweet corn plant by crossing the sweet corn hybrid HMX59BS604 with itself or another sweet corn plant.

FIELD OF THE INVENTION

The present invention relates to the field of agriculture, to new anddistinctive hybrid sweet corn plants, such as hybrid plants designatedHMX59BS604, and to methods of making and using such hybrids.

BACKGROUND OF THE INVENTION

The following description includes information that may be useful inunderstanding the present invention. It is not an admission that any ofthe information provided herein is prior art or relevant to thepresently claimed inventions, or that any publication specifically orimplicitly referenced is prior art.

Sweet Corn is an important and valuable vegetable crop. Thus, acontinuing goal of plant breeders is to develop stable, high yieldingsweet corn hybrids that are agronomically sound or unique. The reasonsfor this goal are to maximize the amount of ears or kernels produced onthe land used (yield) as well as to improve the plant, the ears, husks,eating and processing qualities and/or the plant agronomic andhorticultural qualities. To accomplish this goal, the sweet corn breedermust select and develop sweet corn plants that have the traits thatresult in superior parental lines that combine to produce superiorhybrids.

SUMMARY OF THE INVENTION

The following embodiments and aspects thereof are described inconjunction with systems, tools and methods which are meant to beexemplary, not limiting in scope.

In various embodiments, one or more of the above-described problems havebeen reduced or eliminated, while other embodiments are directed toother improvements.

According to the invention, in some embodiments, there is provided anovel sweet corn hybrid, designated HMX59BS604.

This invention thus relates to the seeds of sweet corn hybrid designatedHMX59BS604, to the plants or parts thereof of sweet corn hybriddesignated HMX59BS604, to plants or parts thereof consisting essentiallyall of the phenotypic and morphological characteristics of sweet cornhybrid designated HMX59BS604 or parts thereof, and/or having all thephysiological and morphological characteristics of sweet corn hybriddesignated HMX59BS604, and/or having one or more or all of thecharacteristics of sweet corn hybrid designated HMX59BS604, listed inTable 1 including but not limited to as determined at the 5%significance level when grown in the same environmental conditions,and/or having one or more of the physiological and morphologicalcharacteristics of sweet corn hybrid designated HMX59BS604, listed inTable 1 including but not limited to as determined at the 5%significance level when grown in the same environmental conditionsand/or having all the physiological and morphological characteristics ofsweet corn hybrid designated HMX59BS604 listed in Table 1 including butnot limited to as determined at the 5% significance level when grown inthe same environmental conditions, and/or having all the physiologicaland morphological characteristics of sweet corn hybrid designatedHMX59BS604 listed in Table 1 when grown in the same environmentalconditions. The invention also relates to variants, mutants and trivialmodifications of the seed or plant of sweet corn hybrid designatedHMX59B 5604.

Plant parts of the sweet corn hybrid plant of the present invention arealso provided, such as, but not limited to, a scion, a rootstock, anear, kernel, leaf, flower, cell, pollen, stalk, roots, anther or ovuleobtained from the hybrid plant. The present invention provides ears andkernels of the sweet corn hybrid of the present invention. Such ears andkernels could be used as fresh products for consumption or in processesresulting in processed products such as food products comprising one ormore harvested part of the hybrid sweet corn designated HMX59BS604, suchas prepared kernels, canned kernels, freeze dried or frozen kernels andthe like. All such products are part of the present invention and thelike. The harvested part or food product can be or can comprise hybridsweet corn fruit from hybrid sweet corn designated HMX59BS604. The foodproducts might have undergone one or more processing steps such as, butnot limited to cutting, washing, mixing, frizzing, canning, etc. Allsuch products are part of the present invention. The present inventionalso provides plant parts or cells, wherein a plant regenerated fromsaid plants parts or cells has one or more, or essentially all of thephenotypic and morphological characteristics of sweet corn hybriddesignated HMX59BS604, such as one or more or all of the characteristicsof sweet corn hybrid designated HMX59BS604, listed in Table 1 includingbut not limited to as determined at the 5% significance level when grownin the same environmental conditions.

The plants and seeds of the present invention include those that may beof an essentially derived variety as defined in section 41(3) of thePlant Variety Protection Act of The United States of America, e.g., avariety that is predominantly derived from sweet corn hybrid designatedHMX59BS604, or from a variety that i) is predominantly derived fromsweet corn hybrid designated HMX59B 5604, while retaining the expressionof the essential characteristics that result from the genotype orcombination of genotypes of sweet corn hybrid designated HMX59BS604; ii)is clearly distinguishable from sweet corn hybrid designated HMX59BS604;and iii) except for differences that result from the act of derivation,conforms to the initial variety in the expression of the essentialcharacteristics that result from the genotype or combination ofgenotypes of the initial variety.

In another aspect, the present invention provides regenerable cells. Insome embodiments, the regenerable cells are for use in tissue culture ofsweet corn hybrid designated HMX59BS604. In some embodiments, the tissueculture is capable of regenerating plants consisting essentially all ofthe phenotypic and morphological characteristics of sweet corn hybriddesignated HMX59BS604, and/or having all the phenotypic andmorphological characteristics of sweet corn hybrid designatedHMX59BS604, and/or having the physiological and morphologicalcharacteristics of sweet corn hybrid designated HMX59BS604, and/orhaving the characteristics of sweet corn hybrid designated HMX59BS604.In one embodiment, the regenerated plants have the characteristics ofsweet corn hybrid designated HMX59BS604 listed in Table 1 including butnot limited to as determined at the 5% significance level when grown inthe same environmental conditions.

In some embodiments, the plant parts and cells used to produce suchtissue cultures will be embryos, meristematic cells, seeds, callus,pollen, leaves, anthers, pistils, roots, root tips, stems, petioles,kernels cotyledons, hypocotyls, ovaries, seed coat, silks, cobs, husks,stalks, endosperm, flowers, axillary buds or the like. Protoplastsproduced from such tissue culture are also included in the presentinvention. The sweet corn shoots, roots and whole plants regeneratedfrom the tissue culture, as well as the ears and kernels produced bysaid regenerated plants are also part of the invention. In someembodiments, the whole plants regenerated from the tissue culture haveone, more than one, or all of the physiological and morphologicalcharacteristics of sweet corn hybrid designated HMX59BS604 listed inTable 1 including but not limited to as determined at the 5%significance level when grown in the same environmental conditions.

The invention also discloses methods for vegetatively propagating aplant of the present invention. In the present application, vegetativelypropagating can be interchangeably used with vegetative reproduction. Insome embodiments, the methods comprise collecting a part of a sweet cornhybrid designated HMX59BS604, and regenerating a plant from said part.In some embodiments, the part can be for example a stem cutting that isrooted into an appropriate medium according to techniques known by theone skilled in the art. Plants, plant parts, ears and kernels thereofproduced by such methods are also included in the present invention. Inanother aspect, the plants, ears and kernels thereof produced by suchmethods consist essentially all of the physiological and morphologicalcharacteristics of sweet corn hybrid designated HMX59BS604, and/orhaving all the physiological and morphological characteristics of sweetcorn hybrid designated HMX59BS604, and/or having the physiological andmorphological characteristics of sweet corn hybrid designatedHMX59BS604, and/or having the characteristics of sweet corn hybriddesignated HMX59BS604. In some embodiments, plants, ears and kernelsproduced by such methods consist of one, more than one, or allphenotypic and morphological characteristics of sweet corn hybriddesignated HMX59BS604 listed in Table 1 including but not limited to asdetermined at the 5% significance level when grown in the sameenvironmental conditions.

Further included in the invention are methods for producing ears andkernels from the sweet corn hybrid designated HMX59BS604. In someembodiments, the methods comprise growing a sweet corn hybrid designatedHMX59BS604 to produce sweet corn ears and kernels. In some embodiments,the methods further comprise harvesting the sweet corn ears. Such earsand their kernels are part of the present invention. In someembodiments, such ear and kernels and/or seeds have all thephysiological and morphological characteristics of ear, kernels, and/orseeds of sweet corn hybrid designated HMX59BS604 (e.g., those listed inTable 1) when grown in the same environmental conditions.

Also included in this invention are methods for producing a sweet cornplant. In some embodiments, the sweet corn plant is produced by crossingthe sweet corn hybrid designated HMX59BS604, with itself or anothersweet corn plant. In some embodiments, the other plant can be a sweetcorn plant. In some embodiments, the other plant can be a sweet cornhybrid or line. When crossed with an inbred line, in some embodiments, a“three-way cross” is produced. When crossed with itself or with another,different sweet corn hybrid, in some embodiments, a “four-way” cross isproduced. Such three and four-way hybrid seeds and plants produced bygrowing said three and four-way hybrid seeds are included in the presentinvention. Methods for producing a three and four-way sweet corn hybridseed comprising crossing sweet corn hybrid designated HMX59BS604 sweetcorn plant with a different sweet corn line or hybrid and harvesting theresultant sweet corn hybrid seed are also part of the invention. Thesweet corn hybrid seeds produced by the method comprising crossing sweetcorn hybrid designated HMX59BS604 sweet corn plant with a differentsweet corn plant and harvesting the resultant sweet corn hybrid seed areincluded in the invention, as are included the sweet corn hybrid plantor parts thereof and seeds produced by said grown sweet corn hybridplants.

Further included in the invention are methods for producing sweet cornseeds and plants made thereof. In some embodiments, the methods compriseself-pollinating the sweet corn hybrid designated HMX59BS604, andharvesting the resultant seeds. Sweet corn seeds produced by such methodare also part of the invention.

In another embodiment, this invention relates to methods for producing asweet corn hybrid designated HMX59BS604 from a collection of seeds. Insome embodiments, the collection contains both seeds of inbred parentlines of sweet corn hybrid designated HMX59BS604, and hybrid seeds ofHMX59BS604. Such a collection of seeds might be a commercial bag ofseeds. In some embodiments, said methods comprise planting thecollection of seeds. When planted, the collection of seeds will produceinbred parent lines of sweet corn hybrid HMX59BS604, and hybrid plantsfrom the hybrid seeds of HMX59BS604. In some embodiments, said inbredparent lines of sweet corn hybrid designated HMX59BS604 are identifiedas having a decreased vigor compared to the other plants (i.e., hybridplants) grown from the collection of seeds. In some embodiments, saiddecreased vigor is due to the inbreeding depression effect and can beidentified for example by a less vigorous appearance for vegetativeand/or reproductive characteristics including a shorter plant height,small ear size, ear and kernel shape, ear color or othercharacteristics. In some embodiments, seeds of the inbred parent linesof the sweet corn hybrid HMX59BS604 are collected, if new inbred plantsthereof are grown and crossed in a controlled manner with each other,the sweet corn hybrid HMX59BS604 will be recreated.

This invention also relates to methods for producing other sweet cornplants derived from sweet corn hybrid HMX59BS604 and to the sweet cornplants derived by the use of those methods.

In some embodiments, such methods for producing a sweet corn plantderived from the hybrid variety HMX59BS604 comprise (a) self-pollinatingthe sweet corn hybrid HMX59BS604 plant at least once to produce aprogeny plant derived from sweet corn hybrid HMX59BS604; In someembodiments, the methods further comprise (b) crossing the progeny plantderived from sweet corn hybrid HMX59B 5604 with itself or a second cornplant to produce a seed of a progeny plant of a subsequent generation;In some embodiments, the methods further comprise (c) growing theprogeny plant of the subsequent generation; In some embodiments, themethods further comprise (d) crossing the progeny plant of thesubsequent generation with itself or a second corn plant to produce asweet corn plant further derived from the sweet corn hybrid HMX59BS604.In further embodiments, steps (b), (c) and/or (d) are repeated for atleast 1, 2, 3, 4, 5, 6, 7, 8, or more generations to produce a sweetcorn plant derived from the sweet corn hybrid variety HMX59BS604. Insome embodiments, within each crossing cycle, the second plant is thesame plant as the second plant in the last crossing cycle. In someembodiments, within each crossing cycle, the second plant is differentfrom the second plant in the last crossing cycle. In some embodiments,within each crossing cycle, the second corn plant is a sweet corn plant.

Another method for producing a sweet corn plant derived from the hybridvariety HMX59BS604, comprises the steps of: (a) crossing the sweet cornhybrid HMX59BS604 plant with a second corn plant to produce a progenyplant derived from sweet corn hybrid HMX59BS604. In some embodiments,the method further comprise (b) crossing the progeny plant derived fromsweet corn hybrid HMX59BS604 with itself or a second sweet corn plant toproduce a seed of a progeny plant of a subsequent generation; In someembodiments, the method further comprise (c) growing the progeny plantof the subsequent generation; In some embodiments, the method furthercomprise (d) crossing the progeny plant of the subsequent generationwith itself or a second corn plant to produce a sweet corn plant derivedfrom the sweet corn hybrid variety HMX59BS604. In a further embodiment,steps (b), (c) and/or (d) are repeated for at least 1, 2, 3, 4, 5, 6, 7,8, or more generations to produce a sweet corn plant derived from thesweet corn hybrid variety HMX59BS604. In some embodiments, within eachcrossing cycle, the second plant is the same plant as the second plantin the last crossing cycle. In some embodiments, within each crossingcycle, the second plant is different from the second plant in the lastcrossing cycle. In some embodiments, within each crossing cycle, thesecond corn plant is a sweet corn plant.

More specifically, the invention comprises methods for producing a malesterile sweet corn plant, an herbicide resistant sweet corn plant, aninsect resistant sweet corn plant, a disease resistant sweet corn plant,a water-stress-tolerant plant, a heat stress tolerant plants, animproved shelf life sweet corn plant, a sweet corn plant with increasedsweetness and flavor, a sweet corn plant with increased sugar content, asweet corn plant with enhanced nutritional quality, a sweet corn plantwith improved nutritional use efficiency, a sweet corn plant withdelayed senescence or controlled ripening and/or plants with improvedsalt tolerance. In some embodiments, said methods comprise transformingthe hybrid designated HMX59BS604 sweet corn plant with nucleic acidmolecules that confer male sterility, herbicide resistance, insectresistance, disease resistance, water-stress tolerance, heat stresstolerance, increased shelf life, increased sweetness and flavor,enhanced nutritional quality, improved nutritional use efficiency,increased sugar content, delayed senescence or controlled ripeningand/or improved salt tolerance, respectively. The transformed sweet cornplants or parts thereof, obtained from the provided methods, includingfor example a male sterile sweet corn plant, an herbicide resistantsweet corn plant, an insect resistant sweet corn plant, a diseaseresistant sweet corn plant, a sweet corn with water stress tolerance, asweet corn plant with heat stress tolerance, a sweet corn plant withincreased sweetness and flavor, a sweet corn plant with increased sugarcontent, a sweet corn with enhanced nutritional quality, a sweet cornplant with improved nutritional use efficiency, a sweet corn plant withdelayed senescence or controlled ripening or a sweet corn plant withimproved salt tolerance are included in the present invention. Plantsmay display one or more of the above listed traits. For the presentinvention and the skilled artisan, disease is understood to include, butnot limited to fungal diseases, viral diseases, bacterial diseases,mycoplasm diseases, or other plant pathogenic diseases and a diseaseresistant plant will encompass a plant resistant to fungal, viral,bacterial, mycoplasm, and other plant pathogens.

In another aspect, the present invention provides methods of introducingor modifying one or more desired trait(s) into the sweet corn hybridHMX59BS604, and plants or seeds obtained from such methods. The desiredtrait(s) may be, but not exclusively, a single gene. In someembodiments, the gene is a dominant allele. In some embodiments, thegene is a partially dominant allele. In some embodiments, the gene is arecessive allele. In some embodiments, the gene or genes will confersuch traits including, but not limited to, male sterility, herbicideresistance, insect resistance, resistance for bacterial, fungal,mycoplasma or viral disease, enhanced plant quality such as improveddrought or salt tolerance, water-stress tolerance, improvedstandability, enhanced plant vigor, improved shelf life, delayedsenescence or controlled ripening, enhanced nutritional quality such asincreased sugar content or increased sweetness, increased texture,flavor and aroma, improved husk length, protection or color, ear shape,uniformity, fill, length or diameter, kernel color, refinement or depth,lodging resistance, yield and recovery, improved fresh cut application,specific aromatic compounds, specific volatiles, flesh texture, specificnutritional components. For the present invention and the skilledartisan, disease is understood to include, but not limited to fungaldiseases, viral diseases, bacterial diseases, mycoplasm diseases, orother plant pathogenic diseases and a disease resistant plant willencompass a plant resistant to fungal, viral, bacterial, mycoplasm, andother plant pathogens. The gene or genes may be naturally occurring orcorn gene(s), mutant(s) or genes modified through the use of NewBreeding Techniques. In some embodiments, the method for introducing thedesired trait(s) is a backcrossing process making use of a series ofbackcrosses to at least one of the parent lines of sweet corn hybridHMX59BS604 during which the desired trait(s) is maintained by selection.The single gene conversion plants that can be obtained by the methodsare included in the present invention.

When dealing with a gene that has been modified, for example through NewBreeding Techniques, the trait (genetic modification) could be directlymodified into the newly developed line/cultivar such as at least one ofthe parent lines of sweet corn hybrid HMX59BS604. Alternatively, if thetrait is not modified into each newly developed line/cultivar such as atleast one of the parent lines of sweet corn hybrid HMX59BS604, anothertypical method used by breeders of ordinary skill in the art toincorporate the modified gene is to take a line already carrying themodified gene and to use such line as a donor line to transfer themodified gene into one or more of the parents of the newly developedhybrid.

The same would apply for a naturally occurring trait or one arising fromspontaneous or induced mutations.

In some embodiments, the backcross breeding process of sweet corn hybridHMX59BS604 comprises (a) crossing one of the parental inbred line plantsof HMX59BS604 with plants of another line that comprise the desiredtrait(s) to produce F1 progeny plants; In some embodiments, the processfurther comprises (b) selecting the F1 progeny plants that have thedesired trait(s); In some embodiments, the process further comprises (c)crossing the selected F1 progeny plants with the parental inbred sweetcorn lines of hybrid HMX59BS604 plants to produce backcross progenyplants; In some embodiments, the process further comprises (d) selectingfor backcross progeny plants that have the desired trait(s) andphysiological and morphological characteristics of the sweet cornparental inbred line of sweet corn hybrid HMX59BS604 to produce selectedbackcross progeny plants; In some embodiments, the process furthercomprises (e) repeating steps (c) and (d) one, two, three, four, fivesix, seven, eight, nine or more times in succession to produce selected,second, third, fourth, fifth, sixth, seventh, eighth, ninth or higherbackcross progeny plants that have the desired trait(s) and otherwiseconsist essentially all of the physiological and morphologicalcharacteristics of the parental inbred sweet corn line of sweet cornHMX59B 5604, and/or have the desired trait(s) and otherwise thephysiological and morphological characteristics of the parental sweetcorn inbred line of sweet corn hybrid HMX59BS604, and/or have all thedesired trait(s) and otherwise the physiological and morphologicalcharacteristics of the parental inbred sweet corn line of sweet cornhybrid HMX59BS604 as determined in Table 1, including but not limited towhen grown in the same environmental conditions or including but notlimited to at a 5% significance level when grown in the sameenvironmental conditions. The sweet corn plants or seed produced by themethods are also part of the invention, as are the sweet corn hybridHMX59BS604 plants that comprised the desired trait. Backcrossingbreeding methods, well known to one skilled in the art of plant breedingwill be further developed in subsequent parts of the specification.

In an embodiment of this invention is a method of making a backcrossconversion of sweet corn hybrid HMX59BS604. In some embodiments, themethod comprises crossing one of the parental sweet corn inbred lineplants of hybrid HMX59BS604 with a donor plant comprising a mutantgene(s), a naturally occurring gene(s), or a gene(s) and/or sequencesmodified through New Breeding Techniques conferring one or more desiredtrait to produce F1 progeny plants; In some embodiments, the methodfurther comprises selecting an F1 progeny plant comprising the naturallyoccurring gene(s), mutant gene(s) or modified gene(s) and/or sequencesconferring the one or more desired trait; In some embodiments, themethod further comprises backcrossing the selected progeny plant to theparental sweet corn inbred line plants of hybrid HMX59BS604. This methodmay further comprise the step of obtaining a molecular marker profile ofthe parental sweet corn inbred line plants of hybrid HMX59BS604 andusing the molecular marker profile to select for the progeny plant withthe desired trait and the molecular marker profile of the parental sweetcorn inbred line plants of hybrid HMX59BS604. In some embodiments, thismethod further comprises crossing the backcross progeny plantHMX59BS604, containing the naturally occurring gene(s), the mutantgene(s) or the modified gene(s) and or sequences conferring the one ormore desired trait with the second parental inbred sweet corn lineplants of sweet corn hybrid HMX59BS604 in order to produce the sweetcorn hybrid HMX59BS604 comprising the naturally occurring gene(s), themutant gene(s) or modified gene(s) and/or sequences conferring the oneor more desired traits. The plants or parts thereof produced by suchmethods are also part of the present invention.

In some embodiments of the invention, the number of loci that may bebackcrossed into the parental sweet corn inbred line of hybridHMX59BS604 is at least 1, 2, 3, 4, 5, or more.

A single locus may contain several genes. A single locus conversion alsoallows for making one or more site specific changes to the plant genome,such as, without limitation, one or more nucleotide change, deletion,insertions, etc. In some embodiments, the single locus conversion isperformed by genome editing, a.k.a. genome editing with engineerednucleases (GEEN). In some embodiments, the genome editing comprisesusing one or more engineered nucleases. In some embodiments, theengineered nucleases include, but are not limited to Zinc fingernucleases (ZFNs), Transcription Activator-Like Effector Nucleases(TALEN5), the CRISPR/Cas system, and engineered meganucleasere-engineered homing endonucleases and endonucleases for DNA guidedgenome editing (Gao et al., Nature Biotechnology (2016), doi:10.1038/nbt.3547). In some embodiments, the single locus conversionchanges one or several nucleotides of the plant genome. Such genomeediting techniques are some of the techniques now known by the personskilled in the art and herein are collectively referred to as “NewBreeding Techniques”.

The invention further provides methods for developing sweet corn plantsin a sweet corn plant breeding program using plant breeding techniquesincluding but not limited to, recurrent selection, backcrossing,pedigree breeding, genomic selection, molecular marker (IsozymeElectrophoresis, Restriction Fragment Length Polymorphisms (RFLPs),Randomly Amplified Polymorphic DNAs (RAPDs), Arbitrarily PrimedPolymerase Chain Reaction (AP-PCR), DNA Amplification Fingerprinting(DAF), Sequence Characterized Amplified Regions (SCARs), AmplifiedFragment Length Polymorphisms (AFLPs), and Simple Sequence Repeats(SSRs) which are also referred to as Microsatellites, Single NucleotidePolymorphism (SNP), etc.) enhanced selection, genetic marker enhancedselection and transformation. Seeds, sweet corn plants, and partsthereof produced by such breeding methods are also part of theinvention.

The invention also relates to variants, mutants and trivialmodifications of the seed or plant of the sweet corn hybrid HMX59BS604or inbred parental lines thereof. Variants, mutants and trivialmodifications of the seed or plant of sweet corn hybrid HMX59BS604 orinbred parental lines thereof can be generated by methods available toone skilled in the art, including but not limited to, mutagenesis (e.g.,chemical mutagenesis, radiation mutagenesis, transposon mutagenesis,insertional mutagenesis, signature tagged mutagenesis, site-directedmutagenesis, and natural mutagenesis), knock-outs/knock-ins, antisenseand RNA interference and other techniques such as the New BreedingTechniques. For more information of mutagenesis in plants, such asagents or protocols, see Acquaah et al. (Principles of plant geneticsand breeding, Wiley-Blackwell, 2007, ISBN 1405136464, 9781405136464,which is herein incorporated by reference in its entity).

The invention also relates to a mutagenized population of the sweet cornhybrid HMX59BS604 and methods of using such populations. In someembodiments, the mutagenized population can be used in screening for newsweet corn plants which comprise one or more or all of the morphologicaland physiological characteristics of sweet corn hybrid HMX59BS604. Insome embodiments, the new sweet corn plants obtained from the screeningprocess comprise all of the morphological and physiologicalcharacteristics of the sweet corn hybrid HMX59BS604 and one or moreadditional or different morphological and physiological characteristicsthat the sweet corn hybrid HMX59BS604 does not have.

This invention also is directed to methods for producing a sweet cornplant by crossing a first parent sweet corn plant with a second parentsweet corn plant wherein either the first or second parent sweet cornplant is a sweet corn hybrid plant of HMX59BS604. Further, both firstand second parent sweet corn plants can come from the sweet corn hybridplant HMX59BS604. Further, the sweet corn hybrid plant HMX59BS604 can beself-pollinated i.e. the pollen of a sweet corn hybrid plant HMX59BS604can pollinate the ovule of the same sweet corn hybrid plant HMX59BS604.When crossed with another sweet corn plant, a hybrid seed is produced.Such methods of hybridization and self-pollination are well known tothose skilled in the art of breeding.

An inbred sweet corn line such as one of the parental lines of sweetcorn hybrid HMX59BS604 has been produced through several cycles ofself-pollination and is therefore to be considered as a homozygous line.An inbred line can also be produced though the dihaploid system whichinvolves doubling the chromosomes from a haploid plant or embryo thusresulting in an inbred line that is genetically stable (homozygous) andcan be reproduced without altering the inbred line. Haploid plants couldbe obtained from haploid embryos that might be produced frommicrospores, pollen, anther cultures or ovary cultures or spontaneoushaploidy. The haploid embryos may then be doubled by chemical treatmentssuch as by colchicine or be doubled autonomously. The haploid embryosmay also be grown into haploid plants and treated to induce thechromosome doubling. In either case, fertile homozygous plants areobtained. A hybrid variety is classically created through thefertilization of an ovule from an inbred parental line by the pollen ofanother, different inbred parental line. Due to the homozygous state ofthe inbred line, the produced gametes carry a copy of each parentalchromosome. As both the ovule and the pollen bring a copy of thearrangement and organization of the genes present in the parental lines,the genome of each parental line is present in the resulting F1 hybrid,theoretically in the arrangement and organization created by the plantbreeder in the original parental line.

As long as the homozygosity of the parental lines is maintained, theresulting hybrid cross shall be stable. The F1 hybrid is then acombination of phenotypic characteristics issued from two arrangementand organization of genes, both created by a person skilled in the artthrough the breeding process.

Still further, this invention also is directed to methods for producinga sweet corn plant derived from sweet corn hybrid HMX59B 5604 bycrossing sweet corn hybrid plant HMX59BS604 with a second corn plant. Insome embodiments, the methods further comprise obtaining a progeny seedfrom the cross. In some embodiments, the methods further comprisegrowing the progeny seed, and possibly repeating the crossing andgrowing steps with the sweet corn hybrid plant HMX59BS604-derived plantfrom 0 to 7 or more times. In some embodiments, the second corn plant isa sweet corn plant. Thus, any such methods using the sweet corn hybridplant HMX59BS604 are part of this invention: selfing, backcrosses,hybrid production, crosses to populations, and the like. All plantsproduced using sweet corn hybrid plant HMX59BS604 as a parent are withinthe scope of this invention, including plants derived from sweet cornhybrid plant HMX59BS604. In some embodiments, such plants have one, morethan one or all physiological and morphological characteristics of thesweet corn hybrid plant HMX59BS604 listed in Table 1 including but notlimited to as determined at the 5% significance level when grown in thesame environmental conditions. In some embodiments, such plants mightexhibit additional and desired characteristics or traits such as highseed yield, high seed germination, seedling vigor, early maturity, highyield, disease tolerance or resistance, lodging resistance andadaptability for soil and climate conditions. Consumer-driven traits,such as a preference for a given ear size, kernel color, kernel texture,kernel taste, kernel firmness, kernel sugar content are other traitsthat may be incorporated into new sweet corn plants developed by thisinvention.

A sweet corn plant can also be propagated vegetatively. A part of theplant, for example a shoot tissue, is collected, and a new plant isobtained from the part. Such part typically comprises an apical meristemof the plant. The collected part is transferred to a medium allowingdevelopment of a plantlet, including for example rooting or developmentof shoots, or is grafted onto a sweet corn plant or a rootstock preparedto support growth of shoot tissue. This is achieved using methods wellknown in the art. Accordingly, in one embodiment, a method ofvegetatively propagating a plant of the present invention comprisescollecting a part of a plant according to the present invention, e.g. ashoot tissue, and obtaining a plantlet from said part. In oneembodiment, a method of vegetatively propagating a plant of the presentinvention comprises: a) collecting tissue of a plant of the presentinvention; b) rooting said proliferated shoots to obtain rootedplantlets. In one embodiment, a method of vegetatively propagating aplant of the present invention comprises: a) collecting tissue of aplant of the present invention; b) cultivating said tissue to obtainproliferated shoots; c) rooting said proliferated shoots to obtainrooted plantlets. In one embodiment, such method further comprisesgrowing a plant from said plantlets. In one embodiment, an ear isharvested from said plant. In one embodiment such ear and kernels and/orseeds and plants have all the physiological and morphologicalcharacteristics of sweet corn hybrid designated HMX59BS604 when grown inthe same environmental conditions. In one embodiment, the ear and/or itskernels is processed into products such as canned kernels, freeze driedor frozen kernels, fresh or prepared ear or kernels and the like.

In some embodiments, the present invention teaches a seed of sweet cornhybrid designated HMX59BS604, wherein a representative sample of seed ofsaid hybrid is deposited under NCIMB No. 43394.

In some embodiments, the present invention teaches a sweet corn plant,or a part thereof, produced by growing the deposited HMX59BS604 seed.

In some embodiments, the present invention teaches sweet corn plantparts, wherein the sweet corn part is selected from the group consistingof: a leaf, a flower, a kernel, an ear, a seed an ovule, pollen, a cell,a rootstock, and a scion.

In some embodiments, the present invention teaches a sweet corn plant,or a part thereof, having all of the characteristics of hybridHMX59BS604 as listed in Table 1 of this application including but notlimited to when grown in the same environmental conditions.

In some embodiments, the present invention teaches a sweet corn plant,or a part thereof, having all of the physiological and morphologicalcharacteristics of hybrid HMX59BS604, wherein a representative sample ofseed of said hybrid was deposited under NCIMB No. 43394.

In some embodiments, the present invention teaches a tissue culture ofregenerable cells produced from the plant or plant part grown from thedeposited HMX59B 5604 seed, wherein cells of the tissue culture areproduced from a plant part selected from the group consisting ofprotoplasts, embryos, meristematic cells, callus, pollen, ovules,flowers, seeds, leaves, roots, root tips, anthers, stems, petioles,fruits, axillary buds, cotyledons and hypocotyls. In some embodiments,the plant part includes protoplasts produced from a plant grown from thedeposited HMX59BS604 seed.

In some embodiments, the present invention teaches a compositioncomprising regenerable cells produced from the plant or plant part grownfrom the deposited hybrid HMX59BS604 seed, or other plant part or plantcell. In some embodiments, the composition comprises a growth media. Insome embodiments, the growth media is solid or a synthetic cultivationmedium. In some embodiments, the composition is a sweet corn plantregenerated from the tissue culture from a plant grown from thedeposited HMX59BS604 seed, said plant having the characteristics ofhybrid HMX59BS604, wherein a representative sample of seed of saidhybrid is deposited under NCIMB No. 43394.

In some embodiments, the present invention teaches a sweet corn ears andkernels produced from the plant grown from the deposited HMX59BS604seed. In one embodiments, such sweet corn ears and kernels have all thephysiological and morphological characteristics of sweet corn hybriddesignated HMX7161 ears and kernels when grown in the same environmentalconditions.

In some embodiments, methods of producing said sweet corn ear comprisea) growing the sweet corn plant from deposited HMX59BS604 seed toproduce a sweet corn ear, and b) harvesting said sweet corn ear. In someembodiments, the present invention also teaches a sweet corn earproduced by the method of producing sweet corn ears and/or kernels asdescribed above. In some embodiments, such ear and kernels have all thephysiological and morphological characteristics of ear and kernels ofsweet corn hybrid designated HMX59BS604 (e.g., those listed in Table 1)when grown in the same environmental conditions

In some embodiments, the present invention teaches methods for producinga sweet corn seed comprising crossing a first parent sweet corn plantwith a second parent sweet corn plant and harvesting the resultant sweetcorn seed, wherein said first parent sweet corn plant and/or secondparent sweet corn plant is the sweet corn plant produced from thedeposited HMX59BS604 seed or a sweet corn plant having all of thecharacteristics of sweet corn hybrid HMX59BS604 as listed in Table 1including but not limited to when grown in the same environmentalconditions.

In some embodiments, the present invention teaches methods for producinga sweet corn seed comprising self-pollinating the sweet corn plant grownfrom the deposited HMX59BS604 seed and harvesting the resultant sweetcorn seed.

In some embodiments, the present invention teaches the seed produced byany of the above described methods.

In some embodiments, the present invention teaches methods ofvegetatively propagating the sweet corn plant grown from the depositedHMX59BS604 seed, said method comprising a) collecting part of a plantgrown from the deposited HMX59BS604 seed and b) regenerating a plantfrom said part.

In some embodiments, the method further comprises harvesting an earand/or kernels from said vegetatively propagated plant.

In some embodiments, the present invention teaches the plant and the earand/or kernels of plants vegetatively propagated from plant parts ofplants grown from the deposited HMX59BS604 seed. In one embodiments,such plant, ear and/or kernels and or seeds have all the physiologicaland morphological characteristics of sweet corn hybrid designated HMX59B5604 plant, ear and/or kernels and or seeds of sweet corn hybridHMX59BS604 (e.g., those listed in Table 1) when grown in the sameenvironmental conditions.

In some embodiments, the present invention teaches methods of producinga sweet corn plant derived from the hybrid variety HMX59BS604. In someembodiment, the methods comprise (a) self-pollinating the plant grownfrom the deposited HMX59BS604 seed at least once to produce a progenyplant derived from sweet corn hybrid HMX59B 5604; In some embodiments,the method further comprises (b) crossing the progeny plant derived fromsweet corn hybrid HMX59BS604 with itself or a second corn plant toproduce a seed of a progeny plant of a subsequent generation; and; (c)growing the progeny plant of the subsequent generation from the seed,and crossing the progeny plant of the subsequent generation with itselfor a second corn plant to produce a sweet corn plant derived from thesweet corn hybrid variety HMX59BS604. In some embodiments said methodsfurther comprise the step of: (d) repeating steps b) and/or c) for atleast 1, 2, 3, 4, 5, 6, 7, or more generation to produce a sweet cornplant derived from the sweet corn hybrid variety HMX59BS604. In someembodiments, the second corn plant is a sweet corn plant.

In some embodiments, the present invention teaches methods of producinga sweet corn plant derived from the hybrid variety HMX59BS604, themethods comprising (a) crossing the plant grown from the depositedHMX59B 5604 seed with a second corn plant to produce a progeny plantderived from sweet corn hybrid HMX59BS604; In some embodiments, themethod further comprises; (b) crossing the progeny plant derived fromsweet corn hybrid HMX59BS604 with itself or a second sweet corn plant toproduce a seed of a progeny plant of a subsequent generation; and; (c)growing the progeny plant of the subsequent generation from the seed;(d) crossing the progeny plant of the subsequent generation with itselfor a second corn plant to produce a sweet corn plant derived from thesweet corn hybrid variety HMX59BS604. In some embodiments said methodsfurther comprise the steps of: (e) repeating step (b), (c) and/or (d)for at least 1, 2, 3, 4, 5, 6, 7 or more generation to produce a sweetcorn plant derived from the sweet corn hybrid HMX59B 5604.

In some embodiments, the present invention teaches plants grown from thedeposited HMX59BS604 seed wherein said plants comprise a single locusconversion. As used herein, the term “a” or “an” refers to one or moreof that entity; for example, “a single locus conversion” refers to oneor more single locus conversions or at least one single locusconversion. As such, the terms “a” (or “an”), “one or more” and “atleast one” are used interchangeably herein. In addition, reference to“an element” by the indefinite article “a” or “an” does not exclude thepossibility that more than one of the elements are present, unless thecontext clearly requires that there is one and only one of the elements.In some embodiments said single locus conversion confers said plantswith a trait selected from the group consisting of male sterility, malefertility, herbicide resistance, insect resistance, resistance forbacterial, fungal, mycoplasma or viral disease, enhanced plant qualitysuch as improved drought or salt tolerance, water stress tolerance,improved standability, enhanced plant vigor, improved shelf life,delayed senescence or controlled ripening, increased nutritional qualitysuch as increased sugar content or increased sweetness, increasedtexture, flavor and aroma, improved fruit length and/or size, protectionfor color, fruit shape, uniformity, length or diameter, refinement ordepth lodging resistance, yield and recovery when compared to a suitablecheck plant. In some embodiments, the check plant is a sweet corn hybridHMX59BS604 not having said single locus conversion. In some embodiments,the at least one single locus conversion is an artificially mutated geneor a gene or nucleotide sequence modified through the use of NewBreeding Techniques.

In some embodiments, the present invention provides a method ofproducing a commodity plant product comprising collecting the commodityplant product from the plant of the present invention. The commodityplant product produced by said method is also part of the presentinvention.

In addition to the exemplary aspects and embodiments described above,further aspects and embodiments will become apparent by study of thefollowing descriptions.

DETAILED DESCRIPTION OF THE INVENTION

Definitions

In the description and tables that follow, a number of terms are used.In order to provide a clear and consistent understanding of thespecification and claims, including the scope to be given such terms,the following definitions are provided:

Allele. An allele is any of one or more alternative forms of a genewhich relate to one trait or characteristic. In a diploid cell ororganism, the two alleles of a given gene occupy corresponding loci on apair of homologous chromosomes.

Backcrossing. Backcrossing is a process in which a breeder repeatedlycrosses hybrid progeny back to one of the parents, for example, a firstgeneration hybrid F₁ with one of the parental genotype of the F₁ hybrid.

Commodity plant product. A “commodity plant product” refers to anycomposition or product that is comprised of material derived from aplant, seed, plant cell, or plant part of the present invention.Commodity plant products may be sold to consumers and can be viable ornonviable. Nonviable commodity products include but are not limited tononviable seeds and grains; processed seeds, seed parts, and plantparts; dehydrated plant tissue, frozen plant tissue, and processed planttissue; seeds and plant parts processed for animal feed for terrestrialand/or aquatic animal consumption, oil, meal, flour, flakes, bran,fiber, paper, tea, coffee, silage, crushed of whole grain, and any otherfood for human or animal consumption; and biomasses and fuel products;and raw material in industry.

Collection of seeds. In the context of the present invention acollection of seeds is a grouping of seeds mainly containing similarkind of seeds, for example hybrid seeds having the inbred line of theinvention as a parental line, but that may also contain, mixed togetherwith this first kind of seeds, a second, different kind of seeds, of oneof the inbred parent lines, for example the inbred line of the presentinvention. A commercial bag of hybrid seeds having the inbred line ofthe invention as a parental line and containing also the inbred lineseeds of the invention would be, for example such a collection of seeds.

Daily heat unit value. The daily heat unit value is calculated asfollows: (the maximum daily temperature+the minimum daily temperature)/2minus 50. All temperatures are in degrees Fahrenheit. The maximumtemperature threshold is 86 degrees, if temperatures exceed this, 86 isused. The minimum temperature threshold is 50 degrees, if temperaturesgo below this, 50 is used.

Decreased vigor. A plant having a decreased vigor in the presentinvention is a plant that, compared to other plants has a less vigorousappearance for vegetative and/or reproductive characteristics includingshorter plant height, small ear size, ear and kernel shape, ear color orother characteristics

Endosperm Type. Endosperm type refers to endosperm genes and otherquality affecting modifiers and types such as starch, sugary alleles(su1, su2, etc.), sugary enhancer (se1) or extender, waxy, amyloseextender, dull, brittle alleles (bt1, bt2, etc.) shrunken-2 (sh2) andother sh alleles, and any combination of these.

Enhanced nutritional quality. The nutritional quality of the sweet cornof the present invention can be enhanced by the introduction of severaltraits comprising a higher endosperm sugar content, increased sweetness,a thinner pericarp, various endosperm types or mutants. Examples ofgenes governing such traits are the “sugary” gene (su1), the “SugaryEnhancer” gene (se1); and the Shrunken-2″ gene (sh2).

Essentially all the physiological and morphological characteristics. Aplant having essentially all the physiological and morphologicalcharacteristics means a plant having the physiological and morphologicalcharacteristics of the recurrent parent, except for the characteristicsderived from the converted gene.

Grafting. Grafting is the operation by which a rootstock is grafted witha scion. The primary motive for grafting is to avoid damages bysoil-born pest and pathogens when genetic or chemical approaches fordisease management are not available. Grafting a susceptible scion ontoa resistant rootstock can provide a resistant cultivar without the needto breed the resistance into the cultivar. In addition, grafting mayenhance tolerance to abiotic stress, increase yield and result in moreefficient water and nutrient uses.

HTU. HTU is the summation of the daily heat unit value calculated fromemergence to harvest.

Immunity to disease(s) and or insect(s). A sweet corn plant which is notsubject to attack or infection by specific disease(s) and or insect(s)is considered immune.

Industrial usage. The industrial usage of the sweet corn of the presentinvention comprises the use of the corn ears or kernels for consumption,whether as fresh products or in canning or freezing industries.

Intermediate resistance to disease(s) and or insect(s). A sweet cornplant that restricts the growth and development of specific disease(s)and or insect(s), but may exhibit a greater range of symptoms or damagecompared to high resistant plants. Intermediate resistant plants willusually show less severe symptoms or damage than susceptible plantvarieties when grown under similar environmental conditions and/orspecific disease(s) and or insect(s) pressure, but may have heavy damageunder heavy pressure. Intermediate resistant (IR) sweet corn plants arenot immune to the disease(s) and or insect(s).

Maturity. In the region of best adaptability, maturity is the number ofdays from seeding to harvesting.

New Breeding Techniques: New breeding techniques are said of various newtechnologies developed and/or used to create new characteristics inplants through genetic variation, the aim being targeted mutagenesis,targeted introduction of new genes or gene silencing (RdDM). Example ofsuch new breeding techniques are targeted sequence changes facilitatedthru the use of Zinc finger nuclease (ZFN) technology (ZFN-1, ZFN-2 andZFN-3, see U.S. Pat. No. 9,145,565, incorporated by reference in itsentirety), Oligonucleotide directed mutagenesis (ODM), Cisgenesis andintragenesis, RNA-dependent DNA methylation (RdDM, which does notnecessarily change nucleotide sequence but can change the biologicalactivity of the sequence), Grafting (on GM rootstock), Reverse breeding,Agro-infiltration (agro-infiltration “sensu stricto”, agro-inoculation,floral dip), Transcription Activator-Like Effector Nucleases (TALEN5,see U.S. Pat. Nos. 8,586,363 and 9,181,535, incorporated by reference intheir entireties), the CRISPR/Cas system (see U.S. Pat. Nos. 8,697,359;8,771,945; 8,795,965; 8,865,406; 8,871,445; 8,889,356; 8,895,308;8,906,616; 8,932,814; 8,945,839; 8,993,233; and 8,999,641, which are allhereby incorporated by reference), engineered meganuclease re-engineeredhoming endonucleases, DNA guided genome editing (Gao et al., NatureBiotechnology (2016), doi: 10.1038/nbt.3547, incorporated by referencein its entirety), and Synthetic genomics). A major part of today'stargeted genome editing, another designation for New BreedingTechniques, is the applications to induce a DNA double strand break(DSB) at a selected location in the genome where the modification isintended. Directed repair of the DSB allows for targeted genome editing.Such applications can be utilized to generate mutations (e.g., targetedmutations or precise native gene editing) as well as precise insertionof genes (e.g., cisgenes, intragenes, or transgenes). The applicationsleading to mutations are often identified as site-directed nuclease(SDN) technology, such as SDN1, SDN2 and SDN3. For SDN1, the outcome isa targeted, non-specific genetic deletion mutation: the position of theDNA DSB is precisely selected, but the DNA repair by the host cell israndom and results in small nucleotide deletions, additions orsubstitutions. For SDN2, a SDN is used to generate a targeted DSB and aDNA repair template (a short DNA sequence identical to the targeted DSBDNA sequence except for one or a few nucleotide changes) is used torepair the DSB: this results in a targeted and predetermined pointmutation in the desired gene of interest. As to the SDN3, the SDN isused along with a DNA repair template that contains new DNA sequence(e.g. gene). The outcome of the technology would be the integration ofthat DNA sequence into the plant genome. The most likely applicationillustrating the use of SDN3 would be the insertion of cisgenic,intragenic, or transgenic expression cassettes at a selected genomelocation. A complete description of each of these techniques can befound in the report made by the Joint Research Center (JRC) Institutefor Prospective Technological Studies of the European Commission in 2011and titled “New plant breeding techniques—State-of-the-art and prospectsfor commercial development”, which is incorporated by reference in itsentirety.

Moisture. The moisture is the actual percentage moisture of the grain atharvest.

Plant adaptability. A plant having good plant adaptability means a plantthat will perform well in different growing conditions and seasons.

Plant Cell. As used herein, the term “plant cell” includes plant cellswhether isolated, in tissue culture or incorporated in a plant or plantpart.

Plant Part. As used herein, the term plant includes plant cells, plantprotoplasts, plant cell tissue cultures from which sweet corn plants canbe regenerated, plant calli, plant clumps and plant cells that areintact in plants or parts of plants, such as embryos, pollen, ovules,flowers, seeds, ears, kernels, rootstock, scions, stems, roots, anthers,pistils, root tips, leaves, meristematic cells, axillary buds,hypocotyls cotyledons, ovaries, seed coat endosperm and the like. Insome embodiments, the plant part at least comprises at least one cell ofsaid plant. In some embodiments, the plant part is further defined as apollen, a meristem, a cell or an ovule. In some embodiments, a plantregenerated from the plant part has all of the phenotypic andmorphological characteristics of a sweet corn hybrid of the presentinvention, including but not limited to as determined at the 5%significance level when grown in the same environmental conditions.

Quantitative Trait Loci (QTL) Quantitative trait loci refer to geneticloci that control to some degree numerically representable traits thatare usually continuously distributed.

Regeneration. Regeneration refers to the development of a plant fromtissue culture.

Resistance to disease(s) and or insect(s). A sweet corn plant thatrestricts the growth and development of specific disease(s) and orinsect(s) under normal disease(s) and or insect(s) attack pressure whencompared to susceptible plants. These sweet corn plants can exhibit somesymptoms or damage under heavy disease(s) and or insect(s) pressure.Resistant (R) sweet corn plants are not immune to the disease(s) and orinsect(s).

Root Lodging. The root lodging is the percentage of plants that rootlodge; i.e., those that lean from the vertical axis at an approximate 30degree angle or greater would be counted as root lodged.

Rootstock. A rootstock is the lower part of a plant capable of receivinga scion in a grafting process.

Scion: A scion is the higher part of a plant capable of being graftedonto a rootstock in a grafting process.

Semi-erect habit. A semi-erect plant has a combination of lateral andupright branching and has an intermediate type habit between a prostateplant habit, having laterally growing branching with fruits most of thetime on the ground and an erect plant habit with branching goingstraight up with fruit being off the ground.

Single gene converted (conversion). Single gene converted (conversion)plants refer to plants which are developed by a plant breeding techniquecalled backcrossing wherein essentially all of the desired morphologicaland physiological characteristics of a plant are recovered in additionto the single gene transferred into the plant via the backcrossingtechnique or via genetic engineering. A single gene converted plant canalso be referred to a plant obtained though mutagenesis or through theuse of some new breeding techniques, whereas the single gene convertedplant has essentially all of the desired morphological and physiologicalcharacteristics of the original variety in addition to the single geneor nucleotide sequence muted or engineered through the New BreedingTechniques.

Susceptible to disease(s) and or insect(s). A sweet corn plant that issusceptible to disease(s) and or insect(s) is defined as a sweet cornplant that has the inability to restrict the growth and development ofspecific disease(s) and or insect(s). Plants that are susceptible willshow damage when infected and are more likely to have heavy damage undermoderate levels of specific disease(s) and or insect(s).

Tolerance to abiotic stresses. A sweet corn plant that is tolerant toabiotic stresses has the ability to endure abiotic stress withoutserious consequences for growth, appearance and yield.

Uniformity. Uniformity, as used herein, describes the similarity betweenplants or plant characteristics which can be a described by qualitativeor quantitative measurements.

Variety. A plant variety as used by one skilled in the art of plantbreeding means a plant grouping within a single botanical taxon of thelowest known rank which can be defined by the expression of thecharacteristics resulting from a given genotype or combination ofphenotypes, distinguished from any other plant grouping by theexpression of at least one of the said characteristics and considered asa unit with regard to its suitability for being propagated unchanged(International convention for the protection of new varieties ofplants).

Yield. The yield is the tons of green corn or green weight per acre. Itcan also be defined as the number of ears per acre or per plant.

Sweet Corn Plants

Sweet corn is a particular type of maize (Zea mays, often referred to ascorn in the United States). Sweet corn naturally mutated from fieldcorn, with origins that are traced back to the Native Americans. Sweetcorn is harvested at an earlier maturity than field corn (before it isdry), for a different purpose, usually fresh produce, canning orfreezing, for human consumption, or to be eaten fresh on the cob,steamed or grilled. It has been bred therefore to be qualitatively andquantitatively different from field corn in a number of respects.

Early varieties, including those used by Native Americans, were theresult of the mutant su1 (“sugary”) allele. The sweet corn (su1)mutation causes the endosperm (storage area) of the seed to accumulateabout two times more sugar than field corn. Today many sweet corn (su1)varieties are available. They contain about 5-10% sugar by weight.

Supersweet corns are varieties of sweet corn which produce higher thannormal levels of sugar, first recognized by University of Illinois atUrbana—Champaign professor John Laughnan. He was investigating twospecific genes in sweet corn, one of which, the sh2 (shrunken2) genecaused the corn to shrivel when dry. After further investigationLaughnan discovered that the endosperm of sh2 sweet corn kernels storeless starch and from 4 to 10 times more sugar than standard sugary sweetcorn. Texture is crispy rather than creamy as with the standard andsugary enhanced varieties. Fresh market shelf life is extended due tothe ability of the kernels to retain moisture and sweetness for longerperiods of time. He published his findings in 1953, disclosing theadvantages of growing supersweet sweet corn, but many corn breederslacked enthusiasm for the new supersweet corn. Illinois Foundation SeedsInc. was the first seed company to release a supersweet corn and it wascalled Illini Xtra-Sweet, but widespread use of supersweet hybrids didnot occur until the early 1980s. The popularity of supersweet corn rosedue to its long shelf life and higher sugar content when compared toconventional sweet corn. This has improved the viability and thus thelong-distance shipping of sweet corn and has enabled manufacturers tocan sweet corn without adding extra sugar.

The third gene mutation to be discovered is the se1 or “sugary enhanced”allele. Sugary enhancer corn results in slightly increased sugar levelsand a more creamy texture due to increased levels of water solublepolysaccharides. Kernels are also generally more tender.

All of the alleles responsible for sweet corn are recessive, so it mustbe isolated from any field corn varieties that release pollen at thesame time; the endosperm develops from genes from both parents, andheterozygous kernels will be tough and starchy. The se1 and su1 allelesdo not need to be isolated from each other as the change in quality ofthe sugary enhancer hybrids will not be that dramatic. Supersweetvarieties containing the sh2 allele must be grown in isolation fromother varieties to avoid cross-pollination and resulting starchiness,either in space (various sources quote minimum isolation distances from100 to 400 feet or 30 to 120 m) or in time (i.e., the supersweet corndoes not pollinate at the same time as other corn in nearby fields).

Sweet corn hybrids come in three colors: yellow, white, and bicolorbased on whether the parental lines are yellow or white.Cross-pollination of a yellow parental line by a white parental linewill result in seed of a hybrid that when grown will produce bicolorears Cross pollination of a yellow kernel hybrid by a bicolor or whitekernel hybrid will not change the kernel color of the yellow hybrid, butmay increase the percentage of yellow kernels on the bicolor or whitekernel hybrids. This is due to the dominant nature of the allele foryellow kernel color. Although there are geographical preferences forcertain kernel colors, there is no relationship between color andsweetness.

There are numerous steps in the development of any novel, desirableplant germplasm. Plant breeding begins with the analysis and definitionof problems and weaknesses of the current germplasm, the establishmentof program goals, and the definition of specific breeding objectives.The next step is selection of germplasm that possesses the traits tomeet the program goals. The goal is to combine in a single variety orhybrid an improved combination of desirable traits from the parentalgermplasm.

In sweet corn these important traits include the ability of the seeds toemerge with vigor and uniformity, a strong plant type that resistslodging, a plant that carries some level of resistance for disease orinsects, a high number of fresh ears or kernels that are produced on aunit of ground, good coverage of the husk leaves over the tip of theear, easy removal of the ear from the stalk with a short shankattachment, a cylindrical ear shape and good balance between the ear'slength and diameter, kernels arranged in 14 to 20 straight rows withgood kernel depth and color, good kernel fill at the tip of the ear andgood canned, frozen and/or fresh eating quality determined by thetenderness, aroma, sweetness and flavor of the sweet corn kernels.

In some embodiments, particularly desirable traits that may beincorporated by this invention are improved resistance to differentviral, fungal, and bacterial pathogens. Important diseases include butare not limited to Northern Leaf blight (caused by Exserohilum turcicum,previously called Helminthosporium turcicum), Common Rust (caused byPuccinia sorghi), “Maize Dwarf Mosaic Virus (caused by MDMV strain A”,Sugar Cane Mosaic Virus (caused by SCMV formally known as MDMV strainB), tropical rust (caused by the fungal pathogen Physopella zeae(Mains), grey leaf spot (fungal disease associated with Cercospora spp),Goss's wilt (caused by the bacterial pathogen Clavibacter michiganensissubsp. nebraskensis (CN)), Stewart's Bacterial Wilt (caused by Paneoeastewartii), High Plains Virus (caused by HP V),” etc. Improvedresistance to insect pests is another desirable trait that may beincorporated into new sweet corn plants developed by this invention.Insect pests affecting sweet corn include, but not limited to Europeancorn borer, corn earworm, corn wireworm, Western bean cutworm fallarmyworm, flea beetles, sap beetles etc.

Sweet Corn Breeding

The goal of sweet corn breeding is to develop new, unique and superiorsweet corn inbred lines and hybrids. The breeder initially selects andcrosses two or more parental lines, followed by repeated selfing andselection, producing many new genetic combinations. Another method usedto develop new, unique and superior sweet corn inbred lines and hybridsoccurs when the breeder selects and crosses two or more parental linesfollowed by haploid induction and chromosome doubling that result in thedevelopment of dihaploid inbred lines. The breeder can theoreticallygenerate billions of different genetic combinations via crossing,selfing and mutations and the same is true for the utilization of thedihaploid breeding method.

During the development of new sweet corn inbreds and hybrids, the sweetcorn breeder uses sweet corn plants, but also non-commercial sweet cornplants, such as plants that may contain characteristics that the breederhas interest in having in its sweet corn inbreds and hybrids. Suchnon-commercial sweet corn plants could be regular field corn, or wildrelatives of corn such as teosinte.

Each year, the plant breeder selects the germplasm to advance to thenext generation. This germplasm is grown under unique and differentgeographical, climatic and soil conditions, and further selections arethen made, during and at the end of the growing season. The inbred linesdeveloped are unpredictable. This unpredictability is because thebreeder's selection occurs in unique environments, with no control atthe DNA level (using conventional breeding procedures or dihaploidbreeding procedures), and with millions of different possible geneticcombinations being generated. A breeder of ordinary skill in the artcannot predict the final resulting lines he develops, except possibly ina very broad and general fashion. This unpredictability results in theexpenditure of large research monies to develop superior new sweet corninbred lines and hybrids.

The development of commercial sweet corn hybrids requires thedevelopment of homozygous inbred lines, the crossing of these lines, andthe evaluation of the F1 hybrid crosses.

Pedigree breeding and recurrent selection breeding methods are used todevelop inbred lines from breeding populations. Breeding programscombine desirable traits from two or more inbred lines or variousbroad-based sources into breeding pools from which inbred lines aredeveloped by selfing and selection of desired phenotypes or through thedihaploid breeding method followed by the selection of desiredphenotypes. The new inbreds are crossed with other inbred lines and thehybrids from these crosses are evaluated to determine which havecommercial potential.

Choice of breeding or selection methods depends on the mode of plantreproduction, the heritability of the trait(s) being improved, and thetype of cultivar used commercially (e.g., F₁ hybrid cultivar, purelinecultivar, etc.). For highly heritable traits, a choice of superiorindividual plants evaluated at a single location will be effective,whereas for traits with low heritability, selection should be based onmean values obtained from replicated evaluations of families of relatedplants. Popular selection methods commonly include pedigree selection,modified pedigree selection, mass selection, recurrent selection, andbackcross breeding.

i. Pedigree Selection

Pedigree breeding is used commonly for the improvement ofself-pollinating crops or inbred lines of cross-pollinating crops. Twoparents possessing favorable, complementary traits are crossed toproduce an F₁. An F₂ population is produced by selfing one or severalF₁s or by intercrossing two F₁s (sib mating). The dihaploid breedingmethod could also be used. Selection of the best individuals is usuallybegun in the F₂ population; then, beginning in the F₃, the bestindividuals in the best families are selected. Replicated testing offamilies, or hybrid combinations involving individuals of thesefamilies, often follows in the F₄ generation to improve theeffectiveness of selection for traits with low heritability. At anadvanced stage of inbreeding (i.e., F6 and F₇), the best lines ormixtures of phenotypically similar lines are tested for potential use asparents of new hybrid cultivars. Similarly, the development of newinbred lines through the dihaploid system requires the selection of thebest inbreds followed by two to five years of testing in hybridcombinations in replicated plots.

The single-seed descent procedure in the strict sense refers to plantinga segregating population, harvesting a sample of one seed per plant, andusing the one-seed sample to plant the next generation. When thepopulation has been advanced from the F2 to the desired level ofinbreeding, the plants from which lines are derived will each trace todifferent F2 individuals. The number of plants in a population declineseach generation due to failure of some seeds to germinate or some plantsto produce at least one seed. As a result, not all of the F2 plantsoriginally sampled in the population will be represented by a progenywhen generation advance is completed.

In a multiple-seed procedure, breeders commonly harvest one or morefruit containing seed from each plant in a population and blend themtogether to form a bulk seed lot. Part of the bulked seed is used toplant the next generation and part is put in reserve. The procedure hasbeen referred to as modified single-seed descent or the bulk technique.

The multiple-seed procedure has been used to save labor at harvest. Itis considerably faster than removing one seed from each fruit by handfor the single seed procedure. The multiple-seed procedure also makes itpossible to plant the same number of seeds of a population eachgeneration of inbreeding. Enough seeds are harvested to make up forthose plants that did not germinate or produce seed.

Descriptions of other breeding methods that are commonly used fordifferent traits and crops can be found in one of several referencebooks (e.g., R. W. Allard, 1960, Principles of Plant Breeding, JohnWiley and Son, pp. 115-161; N. W. Simmonds, 1979, Principles of CropImprovement, Longman Group Limited; W. R. Fehr, 1987, Principles of CropDevelopment, Macmillan Publishing Co.; N. F. Jensen, 1988, PlantBreeding Methodology, John Wiley & Sons).

ii Backcross Breeding

Backcross breeding has been used to transfer genes for a simplyinherited, highly heritable trait into a desirable homozygous cultivaror inbred line which is the recurrent parent. The source of the trait tobe transferred is called the donor parent. The resulting plant isexpected to have the attributes of the recurrent parent (e.g., cultivar)and the desirable trait transferred from the donor parent. After theinitial cross, individuals possessing the phenotype of the recurrentparent and the trait of interest from the donor parent are selected andrepeatedly crossed (backcrossed) to the recurrent parent. The resultingplant is expected to have the attributes of the recurrent parent (e.g.,cultivar) and the desirable trait transferred from the donor parent.

When the term sweet corn hybrid plant is used in the context of thepresent invention, this also includes any sweet corn hybrid plant whereone or more desired trait has been introduced through backcrossingmethods, whether such trait is a naturally occurring one, a mutant, atransgenic one or a gene or a nucleotide sequence modified by the use ofNew Breeding Techniques. Backcrossing methods can be used with thepresent invention to improve or introduce one or more characteristicinto the inbred parental line thus potentially introducing these traitsin to the sweet corn hybrid plant of the present invention. The term“backcrossing” as used herein refers to the repeated crossing of ahybrid progeny back to the recurrent parent, i.e., backcrossing one,two, three, four, five, six, seven, eight, nine, or more times to therecurrent parent. The parental sweet corn plant which contributes thegene or the genes for the desired characteristic is termed thenonrecurrent or donor parent. This terminology refers to the fact thatthe nonrecurrent parent is used one time in the backcross protocol andtherefore does not recur. The parental sweet corn plant to which thegene or genes from the nonrecurrent parent are transferred is known asthe recurrent parent as it is used for several rounds in thebackcrossing protocol.

In a typical backcross protocol, the original inbred of interest(recurrent parent) is crossed to a second inbred (nonrecurrent parent)that carries the gene or genes of interest to be transferred. Theresulting progeny from this cross are then crossed again to therecurrent parent and the process is repeated until a sweet corn plant isobtained wherein all the desired morphological and physiologicalcharacteristics of the recurrent parent are recovered in the convertedplant, generally determined at a 5% significance level when grown in thesame environmental conditions, in addition to the gene or genestransferred from the nonrecurrent parent. It has to be noted that some,one, two, three or more, self-pollination and growing of populationmight be included between two successive backcrosses. Indeed, anappropriate selection in the population produced by theself-pollination, i.e. selection for the desired trait and physiologicaland morphological characteristics of the recurrent parent might beequivalent to one, two or even three additional backcrosses in acontinuous series without rigorous selection, saving then time, moneyand effort to the breeder. A non-limiting example of such a protocolwould be the following: a) the first generation F1 produced by the crossof the recurrent parent A by the donor parent B is backcrossed to parentA, b) selection is practiced for the plants having the desired trait ofparent B, c) selected plant are self-pollinated to produce a populationof plants where selection is practiced for the plants having the desiredtrait of parent B and physiological and morphological characteristics ofparent A, d) the selected plants are backcrossed one, two, three, four,five, six, seven, eight, nine, or more times to parent A to produceselected backcross progeny plants comprising the desired trait of parentB and the physiological and morphological characteristics of parent A.Step (c) may or may not be repeated and included between the backcrossesof step (d).

The selection of a suitable recurrent parent is an important step for asuccessful backcrossing procedure. The goal of a backcross protocol isto alter or substitute one or more trait(s) or characteristic(s) in theoriginal inbred parental line in order to find it then in the hybridmade thereof. To accomplish this, a gene or genes of the recurrentinbred is modified or substituted with the desired gene or genes fromthe nonrecurrent parent, while retaining essentially all of the rest ofthe desired genetic, and therefore the desired physiological andmorphological constitution of the original inbred. The choice of theparticular nonrecurrent parent will depend on the purpose of thebackcross; one of the major purposes is to add some commerciallydesirable, agronomically important trait(s) to the plant. The exactbackcrossing protocol will depend on the characteristic(s) or trait(s)being altered to determine an appropriate testing protocol. Althoughbackcrossing methods are simplified when the characteristic beingtransferred is a single gene and dominant allele, multiple genes andrecessive allele(s) may also be transferred and therefore, backcrossbreeding is by no means restricted to character(s) governed by one or afew genes. In fact the number of genes might be less important that theidentification of the character(s) in the segregating population. Inthis instance it may then be necessary to introduce a test of theprogeny to determine if the desired characteristic(s) has beensuccessfully transferred. Such tests encompass visual inspection, simplecrossing, but also follow up of the characteristic(s) throughgenetically associated markers and molecular assisted breeding tools.For example, selection of progeny containing the transferred trait isdone by direct selection, visual inspection for a trait associated witha dominant allele, while the selection of progeny for a trait that istransferred via a recessive allele, such as the shrunken-2 starch mutantin corn, require selfing the progeny or using molecular markers todetermine which plant carry the recessive allele(s).

In 1981, the backcross method of breeding counted for 17% of the totalbreeding effort for inbred line development in the United States,accordingly to, Hallauer, A. R. et al. (1988) “Corn Breeding” Corn andCorn Improvement, No. 18, pp. 463-481.

The backcross breeding method provides a precise way of improvingvarieties that excel in a large number of attributes but are deficientin a few characteristics. (Page 150 of the Pr. R. W. Allard's 1960 book,published by John Wiley & Sons, Inc., Principles of Plant Breeding). Themethod makes use of a series of backcrosses to the variety to beimproved during which the character or the characters in whichimprovement is sought is maintained by selection. At the end of thebackcrossing the gene or genes being transferred unlike all other genes,will be heterozygous. Selfing after the last backcross produceshomozygosity for this gene pair(s) and, coupled with selection, willresult in a parental line of a hybrid variety with exactly oressentially the same adaptation, yielding ability and qualitycharacteristics of the recurrent parent but superior to that parent inthe particular characteristic(s) for which the improvement program wasundertaken. Therefore, this method provides the plant breeder with ahigh degree of genetic control of his work.

The method is scientifically exact because the morphological andagricultural features of the improved variety could be described inadvance and because a similar variety could, if it were desired, be breda second time by retracing the same steps (Briggs, “Breeding wheatsresistant to bunt by the backcross method”, 1930 Jour. Amer. Soc.Agron., 22: 289-244).

Backcrossing is a powerful mechanism for achieving homozygosity and anypopulation obtained by backcrossing must rapidly converge on thegenotype of the recurrent parent. When backcrossing is made the basis ofa plant breeding program, the genotype of the recurrent parent will betheoretically modified only with regards to genes being transferred,which are maintained in the population by selection.

Successful backcrosses are, for example, the transfer of stem rustresistance from ‘Hope’ wheat to ‘Bart wheat’ and even pursuing thebackcrosses with the transfer of bunt resistance to create ‘Bart 38’,having both resistances. Also highlighted by Allard is the successfultransfer of mildew, leaf spot and wilt resistances in California Commonalfalfa to create ‘Caliverde’. This new ‘Caliverde’ variety producedthrough the backcross process is indistinguishable from CaliforniaCommon except for its resistance to the three named diseases.

One of the advantages of the backcross method is that the breedingprogram can be carried out in almost every environment that will allowthe development of the character being transferred or when usingmolecular markers that can identify the trait of interest.

The backcross technique is not only desirable when breeding for diseaseresistance but also for the adjustment of morphological characters,color characteristics and simply inherited quantitative characters suchas earliness, plant height and seed size and shape. In this regard, amedium grain type variety, ‘Calady’, has been produced by Jones andDavis. As dealing with quantitative characteristics, they selected thedonor parent with the view of sacrificing some of the intensity of thecharacter for which it was chosen, i.e. grain size. ‘Lady Wright’, along grain variety was used as the donor parent and ‘Coloro’, a shortgrain one as the recurrent parent. After four backcrosses, the mediumgrain type variety ‘Calady’ was produced.

iii Open-Pollinated Populations

The improvement of open-pollinated populations of such crops as rye,many maizes and sugar beets, herbage grasses, legumes such as alfalfaand clover, and tropical tree crops such as cacao, coconuts, oil palmand some rubber, depends essentially upon changing gene-frequenciestowards fixation of favorable alleles while maintaining a high (but farfrom maximal) degree of heterozygosity.

Uniformity in such populations is impossible and trueness-to-type in anopen-pollinated variety is a statistical feature of the population as awhole, not a characteristic of individual plants. Thus, theheterogeneity of open-pollinated populations contrasts with thehomogeneity (or virtually so) of inbred lines, clones and hybrids.

Population improvement methods fall naturally into two groups, thosebased on purely phenotypic selection, normally called mass selection,and those based on selection with progeny testing. Interpopulationimprovement utilizes the concept of open breeding populations; allowinggenes to flow from one population to another. Plants in one population(cultivar, strain, ecotype, or any germplasm source) are crossed eithernaturally (e.g., by wind) or by hand or by bees (commonly Apis melliferaL. or Megachile rotundata F.) with plants from other populations.Selection is applied to improve one (or sometimes both) population(s) byisolating plants with desirable traits from both sources.

There are basically two primary methods of open-pollinated populationimprovement.

First, there is the situation in which a population is changed en masseby a chosen selection procedure. The outcome is an improved populationthat is indefinitely propagated by random-mating within itself inisolation.

Second, the synthetic variety attains the same end result as populationimprovement, but is not itself propagated as such; it has to bereconstructed from parental lines or clones. These plant breedingprocedures for improving open-pollinated populations are well known tothose skilled in the art and comprehensive reviews of breedingprocedures routinely used for improving cross-pollinated plants areprovided in numerous texts and articles, including: Allard, Principlesof Plant Breeding, John Wiley & Sons, Inc. (1960); Simmonds, Principlesof Crop Improvement, Longman Group Limited (1979); Hallauer and Miranda,Quantitative Genetics in Maize Breeding, Iowa State University Press(1981); and, Jensen, Plant Breeding Methodology, John Wiley & Sons, Inc.(1988).

A) Mass Selection

Mass and recurrent selections can be used to improve populations ofeither self- or cross-pollinating crops. A genetically variablepopulation of heterozygous individuals is either identified or createdby intercrossing several different parents. The best plants are selectedbased on individual superiority, outstanding progeny, or excellentcombining ability. The selected plants are intercrossed to produce a newpopulation in which further cycles of selection are continued. In massselection, desirable individual plants are chosen, harvested, and theseed composited without progeny testing to produce the followinggeneration. Since selection is based on the maternal parent only, andthere is no control over pollination, mass selection amounts to a formof random mating with selection. As stated above, the purpose of massselection is to increase the proportion of superior genotypes in thepopulation.

B) Synthetics

A synthetic variety is produced by intercrossing a number of genotypesselected for good combining ability in all possible hybrid combinations,with subsequent maintenance of the variety by open pollination. Whetherparents are (more or less inbred) seed-propagated lines, as in somesugar beet and beans (Vicia) or clones, as in herbage grasses, cloversand alfalfa, makes no difference in principle. Parents are selected ongeneral combining ability, sometimes by test crosses or toperosses, moregenerally by polycrosses. Parental seed lines may be deliberately inbred(e.g. by selfing or sib crossing). However, even if the parents are notdeliberately inbred, selection within lines during line maintenance willensure that some inbreeding occurs. Clonal parents will, of course,remain unchanged and highly heterozygous.

Whether a synthetic can go straight from the parental seed productionplot to the farmer or must first undergo one or more cycles ofmultiplication depends on seed production and the scale of demand forseed. In practice, grasses and clovers are generally multiplied once ortwice and are thus considerably removed from the original synthetic.

While mass selection is sometimes used, progeny testing is generallypreferred for polycrosses, because of their operational simplicity andobvious relevance to the objective, namely exploitation of generalcombining ability in a synthetic.

The number of parental lines or clones that enters a synthetic varieswidely. In practice, numbers of parental lines range from 10 to severalhundred, with 100-200 being the average. Broad based synthetics formedfrom 100 or more clones would be expected to be more stable during seedmultiplication than narrow based synthetics.

iv. Hybrids

A hybrid is an individual plant resulting from a cross between parentsof differing genotypes. Commercial hybrids are now used extensively inmany crops, including corn (maize), sorghum, sugarbeet, sunflower andbroccoli and tomato. Hybrids can be formed in a number of differentways, including by crossing two parents directly (single cross hybrids),by crossing a single cross hybrid with another parent (three-way ortriple cross hybrids), or by crossing two different hybrids (four-way ordouble cross hybrids).

Strictly speaking, most individuals in an out breeding (i.e.,open-pollinated) population are hybrids, but the term is usuallyreserved for cases in which the parents are individuals whose genomesare sufficiently distinct for them to be recognized as different speciesor subspecies. Hybrids may be fertile or sterile depending onqualitative and/or quantitative differences in the genomes of the twoparents. Heterosis, or hybrid vigor, is usually associated withincreased heterozygosity that results in increased vigor of growth,survival, and fertility of hybrids as compared with the parental linesthat were used to form the hybrid. Maximum heterosis is usually achievedby crossing two genetically different, highly inbred lines.

Hybrid sweet corn seed is produced by removing the tassels from thefemale parent or by using a male sterile female incorporating manual ormechanical detasseling. Alternate strips of two sweet corn inbreds areplanted in a field, and the pollen-bearing tassels are removed from oneof the inbreds (female). Providing there is sufficient isolation fromsources of foreign corn pollen, the ears of the detasseled inbred willbe fertilized only from the other inbred (male), and the resulting seedis therefore hybrid and will form hybrid plants.

The laborious, and occasionally unreliable, detasseling process can beavoided by using cytoplasmic male-sterile (CMS) inbreds. Plants of a CMSinbred are male sterile as a result of factors resulting from thecytoplasmic, as opposed to the nuclear, genome. Thus, thischaracteristic is inherited exclusively through the female parent incorn plants, since only the female provides cytoplasm to the fertilizedseed. CMS plants are fertilized with pollen from another inbred that isnot male-sterile. Pollen from the second inbred may or may notcontribute genes that make the hybrid plants male-fertile. Seed fromdetasseled fertile corn and CMS produced seed of the same hybrid can beblended to insure that adequate pollen loads are available forfertilization when the hybrid plants are grown.

There are several methods of conferring genetic male sterilityavailable, such as multiple mutant genes at separate locations withinthe genome that confer male sterility, as disclosed in U.S. Pat. Nos.4,654,465 and 4,727,219 to Brar et al. and chromosomal translocations asdescribed by Patterson in U.S. Pat. Nos. 3,861,709 and 3,710,511. Theseand all patents referred to are incorporated by reference. In additionto these methods, Albertsen et al., U.S. Pat. No. 5,432,068 havedeveloped a system of nuclear male sterility which includes: identifyinga gene which is critical to male fertility, silencing this native genewhich is critical to male fertility; removing the native promoter fromthe essential male fertility gene and replacing it with an induciblepromoter; inserting this genetically engineered gene back into theplant; and thus creating a plant that is male sterile because theinducible promoter is not “on” resulting in the male fertility gene notbeing transcribed. Fertility is restored by inducing, or turning “on”,the promoter, which in turn allows the gene that confers male fertilityto be transcribed.

There are many other methods of conferring genetic male sterility in theart, each with its own benefits and drawbacks. These methods use avariety of approaches such as delivering into the plant a gene encodinga cytotoxic substance associated with a male tissue specific promoter oran anti-sense system in which a gene critical to fertility is identifiedand an antisense to that gene is inserted in the plant (see,Fabinjanski, et al. EPO 89/3010153.8 publication no. 329, 308 and PCTapplication PCT/CA90/00037 published as WO 90/08828).

Another version useful in controlling male sterility makes use ofgametocides. Gametocides are not a genetic system, but rather a topicalapplication of chemicals. These chemicals affect cells that are criticalto male fertility. The application of these chemicals affects fertilityin the plants only for the growing season in which the gametocide isapplied (see Carlson, G. R., U.S. Pat. No. 4,936,904). Application ofthe gametocide, timing of the application and genotype specificallyoften limit the usefulness of the approach.

Once the inbreds that give the best hybrid performance have beenidentified, the hybrid seed can be reproduced indefinitely as long asthe homogeneity of the inbred parent is maintained. A single-crosshybrid is produced when two inbred lines are crossed to produce the F1progeny. A double-cross hybrid is produced from four inbred linescrossed in pairs (A×B and C×D) and then the two F1 hybrids are crossedagain (A×B)×(C×D). Much of the hybrid vigor and uniformity exhibited byF1 hybrids is lost in the next generation (F2). Consequently, seed fromF2 hybrid varieties is not used for planting stock.

The production of hybrids is a well-developed industry, involving theisolated production of both the parental lines and the hybrids whichresult from crossing those lines. For a detailed discussion of thehybrid production process, see, e.g., Wright, Commercial Hybrid SeedProduction 8:161-176, In Hybridization of Crop Plants.

v. Bulk Segregation Analysis (BSA)

BSA, a.k.a. bulked segregation analysis, or bulk segregant analysis, isa method described by Michelmore et al. (Michelmore et al., 1991,Identification of markers linked to disease-resistance genes by bulkedsegregant analysis: a rapid method to detect markers in specific genomicregions by using segregating populations. Proceedings of the NationalAcademy of Sciences, USA, 99:9828-9832) and Quarrie et al. (Quarrie etal., 1999, Journal of Experimental Botany, 50(337): 1299-1306).

For BSA of a trait of interest, parental lines with certain differentphenotypes are chosen and crossed to generate F2, doubled haploid orrecombinant inbred populations with QTL analysis. The population is thenphenotyped to identify individual plants or lines having high or lowexpression of the trait. Two DNA bulks are prepared, one from theindividuals having one phenotype (e.g., resistant to virus), and theother from the individuals having reversed phenotype (e.g., susceptibleto virus), and analyzed for allele frequency with molecular markers.Only a few individuals are required in each bulk (e.g., 10 plants each)if the markers are dominant (e.g., RAPDs). More individuals are neededwhen markers are co-dominant (e.g., RFLPs, SNPs or SSRs). Markers linkedto the phenotype can be identified and used for breeding or QTL mapping.

vi. Hand-Pollination Method

Hand pollination describes the crossing of plants via the deliberatefertilization of female ovules with pollen from a desired male parentplant. In some embodiments the donor or recipient female parent and thedonor or recipient male parent line are planted in the same field. Theinbred male parent can be planted earlier or later than the femaleparent to ensure adequate pollen supply at the pollination time. In someembodiments, the male parent and female parent can be planted at a ratioof 1 male parent to 2-6 female parents. The male parent may be plantedat the top of the field for efficient male pollen collection duringpollination. Pollination is started when the female parent flower isready to be fertilized and there is available pollen from the maleparent. Female ear shoots that are ready to open in the following daysare identified, covered with paper cups or small paper bags that preventbee or any other insect from visiting the female flowers, and markedwith any kind of material that can be easily seen the next morning. Themale pollen of the male parent is collected after it is likely thatthere is new pollen available from that days shedding. The coveredfemale flowers of the female parent, which have ear silk showing, areun-covered and pollinated with the collected fresh male pollen of themale parent, starting as soon as the male flower sheds pollen. Thepollinated female flowers are again covered after pollination to preventcontamination by other pollen traveling by wind or by bees and any otherinsects. The pollinated female flowers are also marked. The marked earsare harvested. In some embodiments, the male pollen used forfertilization has been previously collected and stored.

vii. Targeting Induced Local Lesions in Genomes (TILLING)

Breeding schemes of the present application can include crosses withTILLING® plant lines. TILLING® is a method in molecular biology thatallows directed identification of mutations in a specific gene. TILLING®was introduced in 2000, using the model plant Arabidopsis thaliana.TILLING® has since been used as a reverse genetics method in otherorganisms such as zebrafish, corn, wheat, rice, soybean, tomato andlettuce.

The method combines a standard and efficient technique of mutagenesiswith a chemical mutagen (e.g., Ethyl methanesulfonate (EMS)) with asensitive DNA screening-technique that identifies single base mutations(also called point mutations) in a target gene. EcoTILLING is a methodthat uses TILLING® techniques to look for natural mutations inindividuals, usually for population genetics analysis (see Comai, etal., 2003 The Plant Journal 37, 778-786; Gilchrist et al. 2006 Mol.Ecol. 15, 1367-1378; Mejlhede et al. 2006 Plant Breeding 125, 461-467;Nieto et al. 2007 BMC Plant Biology 7, 34-42, each of which isincorporated by reference hereby for all purposes). DEcoTILLING is amodification of TILLING® and EcoTILLING which uses an inexpensive methodto identify fragments (Garvin et al., 2007, DEco-TILLING: An inexpensivemethod for SNP discovery that reduces ascertainment bias. MolecularEcology Notes 7, 735-746).

The TILLING® method relies on the formation of heteroduplexes that areformed when multiple alleles (which could be from a heterozygote or apool of multiple homozygotes and heterozygotes) are amplified in a PCR,heated, and then slowly cooled. As DNA bases are not pairing at themismatch of the two DNA strands (the induced mutation in TILLING® or thenatural mutation or SNP in EcoTILLING), they provoke a shape change inthe double strand DNA fragment which is then cleaved by single strandednucleases. The products are then separated by size on several differentplatforms.

Several TILLING® centers exists over the world that focus onagriculturally important species: UC Davis (USA), focusing on Rice;Purdue University (USA), focusing on Maize; University of BritishColumbia (CA), focusing on Brassica napus; John Innes Centre (UK),focusing on Brassica rapa; Fred Hutchinson Cancer Research, focusing onArabidopsis; Southern Illinois University (USA), focusing on Soybean;John Innes Centre (UK), focusing on Lotus and Medicago; and INRA(France), focusing on Pea and Tomato.

More detailed description on methods and compositions on TILLING® can befound in U.S. Pat. No. 5,994,075, US 2004/0053236 A1, WO 2005/055704,and WO 2005/048692, each of which is hereby incorporated by referencefor all purposes.

Thus in some embodiments, the breeding methods of the present disclosureinclude breeding with one or more TILLING plant lines with one or moreidentified mutations.

viii Mutation Breeding

Mutation breeding is another method of introducing new variation andsubsequent traits into sweet corn plants. Mutations that occurspontaneously or are artificially induced can be useful sources ofvariability for a plant breeder. The goal of artificial mutagenesis isto increase the rate of mutation for a desired characteristic. Mutationrates can be increased by many different means or mutating agentsincluding temperature, long-term seed storage, tissue cultureconditions, radiation (such as X-rays, Gamma rays, neutrons, Betaradiation, or ultraviolet radiation), chemical mutagens (such as baseanalogs like 5-bromo-uracil), antibiotics, alkylating agents (such assulfur mustards, nitrogen mustards, epoxides, ethyleneamines, sulfates,sulfonates, sulfones, or lactones), azide, hydroxylamine, nitrous acidor acridines. Once a desired trait is observed through mutagenesis thetrait may then be incorporated into existing germplasm by traditionalbreeding techniques. Details of mutation breeding can be found in W. R.Fehr, 1993, Principles of Cultivar Development, Macmillan Publishing Co.

New breeding techniques such as the ones involving the uses of ZincFinger Nucleases or oligonucleotide directed mutagenesis shall also beused to generate genetic variability and introduce new traits into sweetcorn varieties.

ix. Double Haploids and Chromosome Doubling

One way to obtain homozygous plants without the need to cross twoparental lines followed by a long selection of the segregating progeny,and/or multiple backcrossing is to produce haploids and then double thechromosomes to form doubled haploids. Haploid plants can occurspontaneously, or may be artificially induced via chemical treatments orby crossing plants with inducer lines (Seymour et al. 2012, PNAS vol.109, pg. 4227-4232; Zhang et al., 2008 Plant Cell Rep. December 27(12)1851-60). The production of haploid progeny can occur via a variety ofmechanisms which can affect the distribution of chromosomes duringgamete formation. The chromosome complements of haploids sometimesdouble spontaneously to produce homozygous doubled haploids (DHs).Mixoploids, which are plants which contain cells having differentploidies, can sometimes arise and may represent plants that areundergoing chromosome doubling so as to spontaneously produce doubledhaploid tissues, organs, shoots, floral parts or plants. Another commontechnique is to induce the formation of double haploid plants with achromosome doubling treatment such as colchicine (El-Hennawy et al.,2011 Vol 56, issue 2 pg. 63-72; Doubled Haploid Production in CropPlants 2003 edited by Maluszynski ISBN 1-4020-1544-5). The production ofdoubled haploid plants yields highly uniform inbred lines and isespecially desirable as an alternative to sexual inbreeding oflonger-generation crops. By producing doubled haploid progeny, thenumber of possible gene combinations for inherited traits is moremanageable. Thus, an efficient doubled haploid technology cansignificantly reduce the time and the cost of inbred and cultivardevelopment.

x. Protoplast Fusion

In another method for breeding plants, protoplast fusion can also beused for the transfer of trait-conferring genomic material from a donorplant to a recipient plant. Protoplast fusion is an induced orspontaneous union, such as a somatic hybridization, between two or moreprotoplasts (cells of which the cell walls are removed by enzymatictreatment) to produce a single bi- or multi-nucleate cell. The fusedcell that may even be obtained with plant species that cannot beinterbred in nature is tissue cultured into a hybrid plant exhibitingthe desirable combination of traits.

xi. Embryo Rescue

Alternatively, embryo rescue may be employed in the transfer ofresistance-conferring genomic material from a donor plant to a recipientplant. Embryo rescue can be used as a procedure to isolate embryos fromcrosses to rapidly move to the next generation of backcrossing orselfing or wherein plants fail to produce viable seed. In this process,the fertilized ovary or immature seed of a plant is tissue cultured tocreate new plants (see Pierik, 1999, In Vitro Culture of Higher Plants,Springer, ISBN 079235267, 9780792352679, which is incorporated herein byreference in its entirety).

Breeding Evaluation

Each breeding program can include a periodic, objective evaluation ofthe efficiency of the breeding procedure. Evaluation criteria varydepending on the goal and objectives, but should include gain fromselection per year based on comparisons to an appropriate standard,overall value of the advanced breeding lines, and number of successfulcultivars produced per unit of input (e.g., per year, per dollarexpended, etc.).

Promising advanced breeding lines are thoroughly tested per se and inhybrid combination and compared to appropriate standards in environmentsrepresentative of the commercial target area(s). The best lines arecandidates for use as parents in new commercial cultivars; those stilldeficient in a few traits may be used as parents to produce newpopulations for further selection or in a backcross program to improvethe parent lines for a specific trait.

In one embodiment, the plants are selected on the basis of one or morephenotypic traits. Skilled persons will readily appreciate that suchtraits include any observable characteristic of the plant, including forexample growth rate, vigor, plant health, maturity, tillering,standability or tolerance to lodging, plant height, stalk weight, leafarea or orientation, height, weight, color, taste, smell, changes in theproduction of one or more compounds by the plant (including for example,metabolites, proteins, drugs, carbohydrates, oils, and any othercompounds).

A most difficult task is the identification of individuals that aregenetically superior, because for most traits the true genotypic valueis masked by other confounding plant traits or environmental factors.One method of identifying a superior plant is to observe its performancerelative to other experimental plants and to a widely grown standardcultivar. If a single observation is inconclusive, replicatedobservations provide a better estimate of its genetic worth.

Proper testing should detect any major faults and establish the level ofsuperiority or improvement over current cultivars. In addition toshowing superior performance, there must be a demand for a new cultivarthat is compatible with industry standards or which creates a newmarket. The introduction of a new cultivar will incur additional coststo the seed producer, the grower, processor and consumer; for specialadvertising and marketing, altered seed and commercial productionpractices, and new product utilization. The testing preceding release ofa new cultivar should take into consideration research and developmentcosts as well as technical superiority of the final cultivar. Forseed-propagated cultivars, it must be feasible to produce seed easilyand economically.

It should be appreciated that in certain embodiments, plants may beselected based on the absence, suppression or inhibition of a certainfeature or trait (such as an undesirable feature or trait) as opposed tothe presence of a certain feature or trait (such as a desirable featureor trait).

Selecting plants based on genotypic information is also envisaged (forexample, including the pattern of plant gene expression, genotype, orpresence of genetic markers). Where the presence of one or more geneticmarker is assessed, the one or more marker may already be known and/orassociated with a particular characteristic of a plant; for example, amarker or markers may be associated with an increased growth rate ormetabolite profile. This information could be used in combination withassessment based on other characteristics in a method of the disclosureto select for a combination of different plant characteristics that maybe desirable. Such techniques may be used to identify novel quantitativetrait loci (QTLs). By way of example, plants may be selected based ongrowth rate, size (including but not limited to weight, height, leafsize, stem size, branching pattern, or the size of any part of theplant), general health, survival, tolerance to adverse physicalenvironments and/or any other characteristic, as described hereinbefore.

Further non-limiting examples include selecting plants based on: speedof seed germination; quantity of biomass produced; increased root,and/or leaf/shoot growth that leads to an increased yield (herbage orgrain or fiber or oil) or biomass production; effects on plant growththat results in an increased seed yield for a crop; effects on plantgrowth which result in an increased yield; effects on plant growth thatlead to an increased resistance or tolerance to disease includingfungal, viral or bacterial diseases, to mycoplasma or to pests such asinsects, mites or nematodes in which damage is measured by decreasedfoliar symptoms such as the incidence of bacterial or fungal lesions, orarea of damaged foliage or reduction in the numbers of nematode cysts orgalls on plant roots, or improvements in plant yield in the presence ofsuch plant pests and diseases; effects on plant growth that lead toincreased metabolite yields; effects on plant growth that lead toimproved aesthetic appeal which may be particularly important in plantsgrown for their form, color or taste, for example the color or the tasteof the kernels.

Molecular Breeding Evaluation Techniques

Selection of plants based on phenotypic or genotypic information may beperformed using techniques such as, but not limited to: high through-putscreening of chemical components of plant origin, sequencing techniquesincluding high through-put sequencing of genetic material, differentialdisplay techniques (including DDRT-PCR, and DD-PCR), nucleic acidmicroarray techniques, RNA-seq (Transcriptome Sequencing), qRTPCR(quantitative real time PCR).

In one embodiment, the evaluating step of a plant breeding programinvolves the identification of desirable traits in progeny plants.Progeny plants can be grown in, or exposed to conditions designed toemphasize a particular trait (e.g. drought conditions for droughttolerance, lower temperatures for freezing tolerant traits). Progenyplants with the highest scores for a particular trait may be used forsubsequent breeding steps.

In some embodiments, plants selected from the evaluation step canexhibit a 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%,65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, 120% or more improvement in aparticular plant trait compared to a control plant.

In other embodiments, the evaluating step of plant breeding comprisesone or more molecular biological tests for genes or other markers. Forexample, the molecular biological test can involve probe hybridizationand/or amplification of nucleic acid (e.g., measuring nucleic aciddensity by Northern or Southern hybridization, PCR) and/or immunologicaldetection (e.g., measuring protein density, such as precipitation andagglutination tests, ELISA (e.g., Lateral Flow test or DAS-ELISA),Western blot, immune labeling, immunosorbent electron microscopy (ISEM),and/or dot blot).

The procedure to perform a nucleic acid hybridization, an amplificationof nucleic acid (e.g., PCR, RT-PCR) or an immunological detection (e.g.,precipitation and agglutination tests, ELISA (e.g., Lateral Flow test orDAS-ELISA), Western blot, RIA, immunogold or immunofluorescent labeling,immunosorbent electron microscopy (ISEM), and/or dot blot tests) areperformed as described elsewhere herein and well-known by one skilled inthe art.

In one embodiment, the evaluating step comprises PCR (semi-quantitativeor quantitative), wherein primers are used to amplify one or morenucleic acid sequences of a desirable gene, or a nucleic acid associatedwith said gene or QTL or a desirable trait (e.g., a co-segregatingnucleic acid, or other marker).

In another embodiment, the evaluating step comprises immunologicaldetection (e.g., precipitation and agglutination tests, ELISA (e.g.,Lateral Flow test or DAS-ELISA), Western blot, RIA, immuno labeling(gold, fluorescent, or other detectable marker), immunosorbent electronmicroscopy (ISEM), and/or dot blot), wherein one or more gene ormarker-specific antibodies are used to detect one or more desirableproteins. In one embodiment, said specific antibody is selected from thegroup consisting of polyclonal antibodies, monoclonal antibodies,antibody fragments, and combination thereof.

Reverse Transcription Polymerase Chain Reaction (RT-PCR) can be utilizedin the present disclosure to determine expression of a gene to assistduring the selection step of a breeding scheme. It is a variant ofpolymerase chain reaction (PCR), a laboratory technique commonly used inmolecular biology to generate many copies of a DNA sequence, a processtermed “amplification”. In RT-PCR, however, RNA strand is first reversetranscribed into its DNA complement (complementary DNA, or cDNA) usingthe enzyme reverse transcriptase, and the resulting cDNA is amplifiedusing traditional or real-time PCR.

RT-PCR utilizes a pair of primers, which are complementary to a definedsequence on each of the two strands of the mRNA. These primers are thenextended by a DNA polymerase and a copy of the strand is made after eachcycle, leading to logarithmic amplification.

RT-PCR includes three major steps. The first step is the reversetranscription (RT) where RNA is reverse transcribed to cDNA using areverse transcriptase and primers. This step is very important in orderto allow the performance of PCR since DNA polymerase can act only on DNAtemplates. The RT step can be performed either in the same tube with PCR(one-step PCR) or in a separate one (two-step PCR) using a temperaturebetween 40° C. and 50° C., depending on the properties of the reversetranscriptase used.

The next step involves the denaturation of the dsDNA at 95° C., so thatthe two strands separate and the primers can bind again at lowertemperatures and begin a new chain reaction. Then, the temperature isdecreased until it reaches the annealing temperature which can varydepending on the set of primers used, their concentration, the probe andits concentration (if used), and the cation concentration. The mainconsideration, of course, when choosing the optimal annealingtemperature is the melting temperature (Tm) of the primers and probes(if used). The annealing temperature chosen for a PCR depends directlyon length and composition of the primers. This is the result of thedifference of hydrogen bonds between A-T (2 bonds) and G-C (3 bonds). Anannealing temperature about 5 degrees below the lowest Tm of the pair ofprimers is usually used.

The final step of PCR amplification is the DNA extension from theprimers which is done by the thermostable Taq DNA polymerase usually at72° C., which is the optimal temperature for the polymerase to work. Thelength of the incubation at each temperature, the temperaturealterations and the number of cycles are controlled by a programmablethermal cycler. The analysis of the PCR products depends on the type ofPCR applied. If a conventional PCR is used, the PCR product is detectedusing for example agarose gel electrophoresis or other polymer gel likepolyacrylamide gels and ethidium bromide (or other nucleic acidstaining).

Conventional RT-PCR is a time-consuming technique with importantlimitations when compared to real time PCR techniques. Furthermore, thespecificity of the assay is mainly determined by the primers, which cangive false-positive results. However, the most important issueconcerning conventional RT-PCR is the fact that it is a semi or even alow quantitative technique, where the amplicon can be visualized onlyafter the amplification ends.

Real time RT-PCR provides a method where the amplicons can be visualizedas the amplification progresses using a fluorescent reporter molecule.There are three major kinds of fluorescent reporters used in real timeRT-PCR, general nonspecific DNA Binding Dyes such as SYBR Green I,TaqMan Probes and Molecular Beacons (including Scorpions).

The real time PCR thermal cycler has a fluorescence detection threshold,below which it cannot discriminate the difference between amplificationgenerated signal and background noise. On the other hand, thefluorescence increases as the amplification progresses and theinstrument performs data acquisition during the annealing step of eachcycle. The number of amplicons will reach the detection baseline after aspecific cycle, which depends on the initial concentration of the targetDNA sequence. The cycle at which the instrument can discriminate theamplification generated fluorescence from the background noise is calledthe threshold cycle (Ct). The higher is the initial DNA concentration,the lower its Ct will be.

Other forms of nucleic acid detection can include next generationsequencing methods such as DNA SEQ or RNA SEQ using any known sequencingplatform including, but not limited to: Roche 454, Solexa GenomeAnalyzer, AB SOLiD, Illumina GA/HiSeq, Ion PGM, Mi Seq, among others(Liu et al., 2012 Journal of Biomedicine and Biotechnology Volume 2012ID 251364; Franca et al., 2002 Quarterly Reviews of Biophysics 35 pg.169-200; Mardis 2008 Genomics and Human Genetics vol. 9 pg. 387-402).

In other embodiments, nucleic acids may be detected with other highthroughput hybridization technologies including microarrays, gene chips,LNA probes, nanoStrings, and fluorescence polarization detection amongothers.

In some embodiments, detection of markers can be achieved at an earlystage of plant growth by harvesting a small tissue sample (e.g., branch,or leaf disk). This approach is preferable when working with largepopulations as it allows breeders to weed out undesirable progeny at anearly stage and conserve growth space and resources for progeny whichshow more promise. In some embodiments the detection of markers isautomated, such that the detection and storage of marker data is handledby a machine. Recent advances in robotics have also led to full serviceanalysis tools capable of handling nucleic acid/protein markerextractions, detection, storage and analysis.

Quantitative Trait Loci

Breeding schemes of the present application can include crosses betweendonor and recipient plants. In some embodiments said donor plantscontain a gene or genes of interest which may confer the plant with adesirable phenotype. The recipient line can be an elite line havingcertain favorable traits for commercial production. In one embodiment,the elite line may contain other genes that also impart said line withthe desired phenotype. When crossed together, the donor and recipientplant may create a progeny plant with combined desirable loci which mayprovide quantitatively additive effect of a particular characteristic.In that case, QTL mapping can be involved to facilitate the breedingprocess.

A QTL (quantitative trait locus) mapping can be applied to determine theparts of the donor plant's genome conferring the desirable phenotype,and facilitate the breeding methods. Inheritance of quantitative traitsor polygenic inheritance refers to the inheritance of a phenotypiccharacteristic that varies in degree and can be attributed to theinteractions between two or more genes and their environment. Though notnecessarily genes themselves, quantitative trait loci (QTLs) arestretches of DNA that are closely linked to the genes that underlie thetrait in question. QTLs can be molecularly identified to help mapregions of the genome that contain genes involved in specifying aquantitative trait. This can be an early step in identifying andsequencing these genes.

Typically, QTLs underlie continuous traits (those traits that varycontinuously, e.g. yield, height, level of resistance to virus, etc.) asopposed to discrete traits (traits that have two or several charactervalues, e.g. smooth vs. wrinkled peas used by Mendel in hisexperiments). Moreover, a single phenotypic trait is usually determinedby many genes. Consequently, many QTLs are associated with a singletrait.

A quantitative trait locus (QTL) is a region of DNA that is associatedwith a particular phenotypic trait. Knowing the number of QTLs thatexplains variation in the phenotypic trait tells about the geneticarchitecture of a trait. It may tell that a trait is controlled by manygenes of small effect, or by a few genes of large effect or by a severalgenes of small effect and few genes of larger effect.

Another use of QTLs is to identify candidate genes underlying a trait.Once a region of DNA is identified as contributing to a phenotype, itcan be sequenced. The DNA sequence of any genes in this region can thenbe compared to a database of DNA for genes whose function is alreadyknown.

In a recent development, classical QTL analyses are combined with geneexpression profiling i.e. by DNA microarrays. Such expression QTLs(e-QTLs) describes cis- and trans-controlling elements for theexpression of often disease-associated genes. Observed epistatic effectshave been found beneficial to identify the gene responsible by across-validation of genes within the interacting loci with metabolicpathway- and scientific literature databases.

QTL mapping is the statistical study of the alleles that occur in alocus and the phenotypes (physical forms or traits) that they produce(see, Meksem and Kahl, The handbook of plant genome mapping: genetic andphysical mapping, 2005, Wiley-VCH, ISBN 3527311165, 9783527311163).Because most traits of interest are governed by more than one gene,defining and studying the entire locus of genes related to a trait giveshope of understanding what effect the genotype of an individual mighthave in the real world.

Statistical analysis is required to demonstrate that different genesinteract with one another and to determine whether they produce asignificant effect on the phenotype. QTLs identify a particular regionof the genome as containing one or several genes, i.e. a cluster ofgenes that is associated with the trait being assayed or measured. Theyare shown as intervals across a chromosome, where the probability ofassociation is plotted for each marker used in the mapping experiment.

To begin, a set of genetic markers must be developed for the species inquestion. A marker is an identifiable region of variable DNA. Biologistsare interested in understanding the genetic basis of phenotypes(physical traits). The aim is to find a marker that is significantlymore likely to co-occur with the trait than expected by chance, that is,a marker that has a statistical association with the trait. Ideally,they would be able to find the specific gene or genes in question, butthis is a long and difficult undertaking. Instead, they can more readilyfind regions of DNA that are very close to the genes in question. When aQTL is found, it is often not the actual gene underlying the phenotypictrait, but rather a region of DNA that is closely linked with the gene.

For organisms whose genomes are known, one might now try to excludegenes in the identified region whose function is known with somecertainty not to be connected with the trait in question. If the genomeis not available, it may be an option to sequence the identified regionand determine the putative functions of genes by their similarity togenes with known function, usually in other genomes. This can be doneusing BLAST, an online tool that allows users to enter a primarysequence and search for similar sequences within the BLAST database ofgenes from various organisms.

Another interest of statistical geneticists using QTL mapping is todetermine the complexity of the genetic architecture underlying aphenotypic trait. For example, they may be interested in knowing whethera phenotype is shaped by many independent loci, or by a few loci, andhow do those loci interact. This can provide information on how thephenotype may be evolving.

Molecular markers are used for the visualization of differences innucleic acid sequences. This visualization is possible due to DNA-DNAhybridization techniques (RFLP) and/or due to techniques using thepolymerase chain reaction (e.g. STS, SNPs, microsatellites, AFLP). Alldifferences between two parental genotypes will segregate in a mappingpopulation based on the cross of these parental genotypes. Thesegregation of the different markers may be compared and recombinationfrequencies can be calculated. The recombination frequencies ofmolecular markers on different chromosomes are generally 50%. Betweenmolecular markers located on the same chromosome the recombinationfrequency depends on the distance between the markers. A lowrecombination frequency usually corresponds to a low distance betweenmarkers on a chromosome. Comparing all recombination frequencies willresult in the most logical order of the molecular markers on thechromosomes. This most logical order can be depicted in a linkage map(Paterson, 1996, Genome Mapping in Plants. R. G. Landes, Austin.). Agroup of adjacent or contiguous markers on the linkage map that isassociated to a reduced disease incidence and/or a reduced lesion growthrate pinpoints the position of a QTL.

The nucleic acid sequence of a QTL may be determined by methods known tothe skilled person. For instance, a nucleic acid sequence comprisingsaid QTL or a resistance-conferring part thereof may be isolated from adonor plant by fragmenting the genome of said plant and selecting thosefragments harboring one or more markers indicative of said QTL.Subsequently, or alternatively, the marker sequences (or parts thereof)indicative of said QTL may be used as (PCR) amplification primers, inorder to amplify a nucleic acid sequence comprising said QTL from agenomic nucleic acid sample or a genome fragment obtained from saidplant. The amplified sequence may then be purified in order to obtainthe isolated QTL. The nucleotide sequence of the QTL, and/or of anyadditional markers comprised therein, may then be obtained by standardsequencing methods.

One or more such QTLs associated with a desirable trait in a donor plantcan be transferred to a recipient plant to incorporate the desirabletrait into progeny plants by transferring and/or breeding methods.

In one embodiment, an advanced backcross QTL analysis (AB-QTL) is usedto discover the nucleotide sequence or the QTLs responsible for theresistance of a plant. Such method was proposed by Tanksley and Nelsonin 1996 (Tanksley and Nelson, 1996, Advanced backcross QTL analysis: amethod for simultaneous discovery and transfer of valuable QTL fromun-adapted germplasm into elite breeding lines. Theor Appl Genet92:191-203) as a new breeding method that integrates the process of QTLdiscovery with variety development, by simultaneously identifying andtransferring useful QTL alleles from un-adapted (e.g., land races, wildspecies) to elite germplasm, thus broadening the genetic diversityavailable for breeding. AB-QTL strategy was initially developed andtested in tomato, and has been adapted for use in other crops includingrice, maize, wheat, pepper, barley, and bean. Once favorable QTL allelesare detected, only a few additional marker-assisted generations arerequired to generate near isogenic lines (NILs) or introgression lines(ILs) that can be field tested in order to confirm the QTL effect andsubsequently used for variety development.

Isogenic lines in which favorable QTL alleles have been fixed can begenerated by systematic backcrossing and introgressing of marker-defineddonor segments in the recurrent parent background. These isogenic linesare referred to as near isogenic lines (NILs), introgression lines(ILs), backcross inbred lines (BILs), backcross recombinant inbred lines(BCRIL), recombinant chromosome substitution lines (RCSLs), chromosomesegment substitution lines (CSSLs), and stepped aligned inbredrecombinant strains (STAIRSs). An introgression line in plant molecularbiology is a line of a crop species that contains genetic materialderived from a similar species. ILs represent NILs with relatively largeaverage introgression length, while BILs and BCRILs are backcrosspopulations generally containing multiple donor introgressions per line.As used herein, the term “introgression lines or ILs” refers to plantlines containing a single marker defined homozygous donor segment, andthe term “pre-ILs” refers to lines which still contain multiplehomozygous and/or heterozygous donor segments.

To enhance the rate of progress of introgression breeding, a geneticinfrastructure of exotic libraries can be developed. Such an exoticlibrary comprises a set of introgression lines, each of which has asingle, possibly homozygous, marker-defined chromosomal segment thatoriginates from a donor exotic parent, in an otherwise homogenous elitegenetic background, so that the entire donor genome would be representedin a set of introgression lines. A collection of such introgressionlines is referred as libraries of introgression lines or IL libraries(ILLs). The lines of an ILL cover usually the complete genome of thedonor, or the part of interest. Introgression lines allow the study ofquantitative trait loci, but also the creation of new varieties byintroducing exotic traits. High resolution mapping of QTL using ILLsenable breeders to assess whether the effect on the phenotype is due toa single QTL or to several tightly linked QTL affecting the same trait.In addition, sub-ILs can be developed to discover molecular markerswhich are more tightly linked to the QTL of interest, which can be usedfor marker-assisted breeding (MAB). Multiple introgression lines can bedeveloped when the introgression of a single QTL is not sufficient toresult in a substantial improvement in agriculturally important traits(Gur and Zamir, Unused natural variation can lift yield barriers inplant breeding, 2004, PLoS Biol.; 2(10):e245).

Plant Transformation

In some embodiments, the present invention provides transformed sweetcorn plants or parts thereof that have been transformed so that itsgenetic material contains one or more transgenes, preferably operablylinked to one or more regulatory elements. Also, the invention providesmethods for producing a sweet corn plant containing in its geneticmaterial one or more transgenes, preferably operably linked to one ormore regulatory elements, by crossing transformed sweet corn plants witha second plant of another sweet corn, so that the genetic material ofthe progeny that results from the cross contains the transgene(s),preferably operably linked to one or more regulatory elements. Theinvention also provides methods for producing a sweet corn plant thatcontains in its genetic material one or more transgene(s), wherein themethod comprises crossing a sweet corn with a second plant of anothersweet corn which contains one or more transgene(s) operably linked toone or more regulatory element(s) so that the genetic material of theprogeny that results from the cross contains the transgene(s) operablylinked to one or more regulatory element(s). Transgenic sweet cornplants, or parts thereof produced by the method are in the scope of thepresent invention.

With the advent of molecular biological techniques that have allowed theisolation and characterization of genes that encode specific proteinproducts, scientists in the field of plant biology developed a stronginterest in engineering the genome of plants to contain and expressforeign genes, or additional, or modified versions of native, orendogenous, genes (perhaps driven by different promoters) in order toalter the traits of a plant in a specific manner. Such foreignadditional and/or modified genes are referred to herein collectively as“transgenes.” Over the last fifteen to twenty years several methods forproducing transgenic plants have been developed, and the presentinvention, in particular embodiments, also relates to transformedversions of the claimed sweet corn hybrid plant HMX59BS604.

Numerous methods for plant transformation have been developed, includingbiological and physical, plant transformation protocols. See, forexample, Miki et al., “Procedures for Introducing Foreign DNA intoPlants” in Methods in Plant Molecular Biology and Biotechnology, GlickB. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993) pages67-88. In addition, expression vectors and in vitro culture methods forplant cell or tissue transformation and regeneration of plants areavailable. See, for example, Gruber et al., “Vectors for PlantTransformation” in Methods in Plant Molecular Biology and Biotechnology,Glick B. R. and Thompson, J. E. Eds. (CRC Press, Inc., Boca Raton, 1993)pages 89-119.

i Agrobacterium-Mediated Transformation

One method for introducing an expression vector into plants is based onthe natural transformation system of Agrobacterium. See, for example,Horsch et al., Science 227:1229 (1985), Jefferson et al., Embo J.3901-390764, (1987), Diant, et al., Molecular Breeding, 3:1, 75-86(1997), Valles et al., PI. Cell. Rep. 145-148:13 (1984). A. tumefaciensand A. rhizogenes are plant pathogenic soil bacteria which geneticallytransform plant cells. The Ti and Ri plasmids of A. tumefaciens and A.rhizogenes, respectively, carry genes responsible for genetictransformation of the plant. See, for example, Kado, C. I., Crit. Rev.Plant Sci. 10:1 (1991). Descriptions of Agrobacterium vector systems andmethods for Agrobacterium-mediated gene transfer are provided by Gruberet al., supra, Miki et al., supra, and Moloney et al., Plant CellReports 8:238 (1989). See also, U.S. Pat. No. 5,591,616 issued Jan. 7,1997.

ii. Direct Gene Transfer

Despite the fact the host range for Agrobacterium-mediatedtransformation is broad, some major cereal crop species and gymnospermshave generally been recalcitrant to this mode of gene transfer, eventhough some success has been achieved in rice and corn. Hiei et al., ThePlant Journal 6:271-282 (1994) and U.S. Pat. No. 5,591,616 issued Jan.7, 1997. Several methods of plant transformation, collectively referredto as direct gene transfer, have been developed as an alternative toAgrobacterium-mediated transformation.

A generally applicable method of plant transformation ismicroprojectile-mediated transformation wherein DNA is carried on thesurface of microprojectiles measuring 1 to 4 micron. The expressionvector is introduced into plant tissues with a biolistic device thataccelerates the microprojectiles to speeds of 300 to 600 m/s which issufficient to penetrate plant cell walls and membranes. Russell, D. R.,et al., Pl. Cell. Rep., 12, 165-169 (1993); Aragao, F. J. L., et al.,Plant Mol. Biol., 20, 357-359 (1992); Aragao, Theor. Appl. Genet.,93:142-150 (1996); Kim, J.; Minamikawa, T., Plant Science, 117:131-138(1996); Sanford et al., Part. Sci. Technol. 5:27 (1987), Sanford, J. C.,Trends Biotech. 6:299 (1988), Klein et al., BioTechnology 6:559-563(1988), Sanford, J. C., Physiol Plant 7:206 (1990), Klein et al.,BioTechnology 10:268 (1992). Gray et al., Plant Cell Tissue and OrganCulture. 1994, 37:2, 179-184.

Another method for physical delivery of DNA to plants is sonication oftarget cells. Zhang et al., BioTechnology 9:996 (1991). Alternatively,liposome and spheroplast fusion have been used to introduce expressionvectors into plants. Deshayes et al., EMBO J., 4:2731 (1985), Christouet al., Proc Natl. Acad. Sci. U.S.A. 84:3962 (1987). Direct uptake ofDNA into protoplasts using CaCl₂ precipitation, polyvinyl alcohol orpoly-L-ornithine has also been reported. Hain et al., Mol. Gen. Genet.199:161 (1985) and Draper et al., Plant Cell Physiol. 23:451 (1982).Electroporation of protoplasts and whole cells and tissues have alsobeen described. D'Halluin et al., Plant Cell 4:1495-1505 (1992) andSpencer et al., Plant Mol. Biol. 24:51-61 (1994).

Any DNA sequence(s), whether from a different species or from the samespecies that is inserted into the genome using transformation isreferred to herein collectively as “transgenes”. In some embodiments ofthe invention, a transformed variant of sweet corn hybrid HMX59BS604 maycontain at least one transgene but could contain at least 1, 2, 3, 4, 5,6, 7, 8, 9, or 10 transgenes. In another embodiment of the invention, atransformed variant of the another sweet corn plant used as the donorline may contain at least one transgene but could contain at least 1, 2,3, 4, 5, 6, 7, 8, 9, or 10 transgenes.

Following transformation of sweet corn target tissues, expression of theabove-described selectable marker genes allows for preferentialselection of transformed cells, tissues and/or plants, usingregeneration and selection methods now well known in the art.

The foregoing methods for transformation would typically be used forproducing a transgenic inbred line or a transgenic hybrid plant. Thetransgenic inbred line could then be crossed, with another(non-transformed or transformed) inbred line, in order to produce a newtransgenic inbred line or plant. Alternatively, a genetic trait whichhas been engineered into a particular sweet corn plant using theforegoing transformation techniques could be moved into another sweetcorn plant using traditional backcrossing techniques that are well knownin the plant breeding arts. For example, a backcrossing approach couldbe used to move an engineered trait from a public, non-elite inbred lineinto an elite inbred line, or from an inbred line containing a foreigngene in its genome into an inbred line or lines which do not containthat gene. As used herein, “crossing” can refer to a simple X by Ycross, or the process of backcrossing, depending on the context.

iii Selection

For efficient plant transformation, a selection method must be employedsuch that whole plants are regenerated from a single transformed celland every cell of the transformed plant carries the DNA of interest.These methods can employ positive selection, whereby a foreign gene issupplied to a plant cell that allows it to utilize a substrate presentin the medium that it otherwise could not use, such as mannose or xylose(for example, refer U.S. Pat. Nos. 5,767,378; 5,994,629). Moretypically, however, negative selection is used because it is moreefficient, utilizing selective agents such as herbicides or antibioticsthat either kill or inhibit the growth of non-transformed plant cellsand reducing the possibility of chimeras. Resistance genes that areeffective against negative selective agents are provided on theintroduced foreign DNA used for the plant transformation. For example,one of the most popular selective agents used is the antibiotickanamycin, together with the resistance gene neomycin phosphotransferase(nptII), which confers resistance to kanamycin and related antibiotics(see, for example, Messing & Vierra, Gene 19: 259-268 (1982); Bevan etal., Nature 304:184-187 (1983)). However, many different antibiotics andantibiotic resistance genes can be used for transformation purposes(refer U.S. Pat. Nos. 5,034,322, 6,174,724 and 6,255,560). In addition,several herbicides and herbicide resistance genes have been used fortransformation purposes, including the bar gene, which confersresistance to the herbicide phosphinothricin (White et al., Nucl AcidsRes 18: 1062 (1990), Spencer et al., Theor Appl Genet 79: 625-631(1990),U.S. Pat. Nos. 4,795,855, 5,378,824 and 6,107,549). In addition, thedhfr gene, which confers resistance to the anticancer agentmethotrexate, has been used for selection (Bourouis et al., EMBO J.2(7): 1099-1104 (1983).

Additional selectable marker genes of bacterial origin that conferresistance to antibiotics include gentamycin acetyl transferase,streptomycin phosphotransferase, and aminoglycoside-3′-adenyltransferase, the bleomycin resistance determinant. Hayford et al., PlantPhysiol. 86:1216 (1988), Jones et al., Mol. Gen. Genet., 210:86 (1987),Svab et al., Plant Mol. Biol. 14:197 (1990), Hille et al., Plant Mol.Biol. 7:171 (1986). Other selectable marker genes confer resistance toherbicides such as glyphosate, glufosinate or bromoxynil. Comai et al.,Nature 317:741-744 (1985), Gordon-Kamm et al., Plant Cell 2:603-618(1990) and Stalker et al., Science 242:419-423 (1988).

Other selectable marker genes for plant transformation are not ofbacterial origin. These genes include, for example, mouse dihydrofolatereductase, plant 5-enolpyruvylshikimate-3-phosphate synthase and plantacetolactate synthase. Eichholtz et al., Somatic Cell Mol. Genet. 13:67(1987), Shah et al., Science 233:478 (1986), Charest et al., Plant CellRep. 8:643 (1990).

Another class of marker genes for plant transformation requiresscreening of presumptively transformed plant cells rather than directgenetic selection of transformed cells for resistance to a toxicsubstance such as an antibiotic. These genes are particularly useful toquantify or visualize the spatial pattern of expression of a gene inspecific tissues and are frequently referred to as reporter genesbecause they can be fused to a gene or gene regulatory sequence for theinvestigation of gene expression. Commonly used genes for screeningpresumptively transformed cells include beta-glucuronidase (GUS,beta-galactosidase, luciferase and chloramphenicol acetyltransferase.Jefferson, R. A., Plant Mol. Biol. Rep. 5:387 (1987), Teeri et al., EMBOJ. 8:343 (1989), Koncz et al., Proc. Natl. Acad. Sci U.S.A. 84:131(1987), DeBlock et al., EMBO J. 3:1681 (1984), Valles et al., Plant CellReport 3:3-4 145-148 (1994), Shetty et al., FoodBiotechnology 11:2111-128 (1997)

In vivo methods for visualizing GUS activity that do not requiredestruction of plant tissue are also available. However, these in vivomethods for visualizing GUS activity have not proven useful for recoveryof transformed cells because of low sensitivity, high fluorescentbackgrounds and limitations associated with the use of luciferase genesas selectable markers.

A gene encoding Green Fluorescent Protein (GFP) has been utilized as amarker for gene expression in prokaryotic and eukaryotic cells. Chalfieet al., Science 263:802 (1994). GFP and mutants of GFP may be used asscreenable markers.

iv Expression Vectors

Genes can be introduced in a site directed fashion using homologousrecombination. Homologous recombination permits site-specificmodifications in endogenous genes and thus inherited or acquiredmutations may be corrected, and/or novel alterations may be engineeredinto the genome. Homologous recombination and site-directed integrationin plants are discussed in, for example, U.S. Pat. Nos. 5,451,513;5,501,967 and 5,527,695.

The expression control elements used to regulate the expression of agiven protein can either be the expression control element that isnormally found associated with the coding sequence (homologousexpression element) or can be a heterologous expression control element.A variety of homologous and heterologous expression control elements areknown in the art and can readily be used to make expression units foruse in the present invention. Transcription initiation regions, forexample, can include any of the various opine initiation regions, suchas octopine, mannopine, nopaline and the like that are found in the Tiplasmids of Agrobacterium tumefaciens. Alternatively, plant viralpromoters can also be used, such as the cauliflower mosaic virus 19S and35S promoters (CaMV 19S and CaMV 35S promoters, respectively) to controlgene expression in a plant (U.S. Pat. Nos. 5,352,605; 5,530,196 and5,858,742 for example). Enhancer sequences derived from the CaMV canalso be utilized (U.S. Pat. Nos. 5,164,316; 5,196,525; 5,322,938;5,530,196; 5,352,605; 5,359,142; and 5,858,742 for example). Lastly,plant promoters such as prolifera promoter, fruit specific promoters,Ap3 promoter, heat shock promoters, seed specific promoters, etc. canalso be used.

Either a gamete-specific promoter, a constitutive promoter (such as theCaMV or Nos promoter), an organ-specific promoter (such as the E8promoter from tomato), or an inducible promoter is typically ligated tothe protein or antisense encoding region using standard techniques knownin the art. The expression unit may be further optimized by employingsupplemental elements such as transcription terminators and/or enhancerelements.

Thus, for expression in plants, the expression units will typicallycontain, in addition to the protein sequence, a plant promoter region, atranscription initiation site and a transcription termination sequence.Unique restriction enzyme sites at the 5′ and 3′ ends of the expressionunit are typically included to allow for easy insertion into apre-existing vector.

In the construction of heterologous promoter/structural gene orantisense combinations, the promoter is preferably positioned about thesame distance from the heterologous transcription start site as it isfrom the transcription start site in its natural setting. As is known inthe art, however, some variation in this distance can be accommodatedwithout loss of promoter function.

In addition to a promoter sequence, the expression cassette can alsocontain a transcription termination region downstream of the structuralgene to provide for efficient termination. The termination region may beobtained from the same gene as the promoter sequence or may be obtainedfrom different genes. If the mRNA encoded by the structural gene is tobe efficiently processed, DNA sequences which direct polyadenylation ofthe RNA are also commonly added to the vector construct. Polyadenylationsequences include, but are not limited to the Agrobacterium octopinesynthase signal (Gielen et al., EMBO J 3:835-846 (1984)) or the nopalinesynthase signal (Depicker et al., Mol. and Appl. Genet. 1:561-573(1982)). The resulting expression unit is ligated into or otherwiseconstructed to be included in a vector that is appropriate for higherplant transformation. One or more expression units may be included inthe same vector. The vector will typically contain a selectable markergene expression unit by which transformed plant cells can be identifiedin culture. Usually, the marker gene will encode resistance to anantibiotic, such as G418, hygromycin, bleomycin, kanamycin, orgentamicin or to an herbicide, such as glyphosate (Round-Up) orglufosinate (BASTA) or atrazine. Replication sequences, of bacterial orviral origin, are generally also included to allow the vector to becloned in a bacterial or phage host; preferably a broad host range forprokaryotic origin of replication is included. A selectable marker forbacteria may also be included to allow selection of bacterial cellsbearing the desired construct. Suitable prokaryotic selectable markersinclude resistance to antibiotics such as ampicillin, kanamycin ortetracycline. Other DNA sequences encoding additional functions may alsobe present in the vector, as is known in the art. For instance, in thecase of Agrobacterium transformations, T-DNA sequences will also beincluded for subsequent transfer to plant chromosomes.

To introduce a desired gene or set of genes by conventional methodsrequires a sexual cross between two lines, and then repeatedback-crossing between hybrid offspring and one of the parents until aplant with the desired characteristics is obtained. This process,however, is restricted to plants that can sexually hybridize, and genesin addition to the desired gene will be transferred.

Recombinant DNA techniques allow plant researchers to circumvent theselimitations by enabling plant geneticists to identify and clone specificgenes for desirable traits, such as improved fatty acid composition, andto introduce these genes into already useful varieties of plants. Oncethe foreign genes have been introduced into a plant, that plant can thenbe used in conventional plant breeding schemes (e.g., pedigree breeding,single-seed-descent breeding schemes, reciprocal recurrent selection) toproduce progeny which also contain the gene of interest.

v Promoters

Genes included in expression vectors must be driven by nucleotidesequence comprising a regulatory element, for example, a promoter.Several types of promoters are now well known in the transformationarts, as are other regulatory elements that can be used alone or incombination with promoters.

As used herein, “promoter” includes reference to a region of DNAupstream from the start of transcription and involved in recognition andbinding of RNA polymerase and other proteins to initiate transcription.A “plant promoter” is a promoter capable of initiating transcription inplant cells. Examples of promoters under developmental control includepromoters that preferentially initiate transcription in certain organs,such as leaves, roots, seeds and tissues such as fibers, xylem vessels,tracheids, or sclerenchyma. Such promoters are referred to as“tissue-preferred”. Promoters which initiate transcription only incertain tissue are referred to as “tissue-specific”. A “cell type”specific promoter primarily drives expression in certain cell types inone or more organs, for example, vascular cells in roots or leaves. An“inducible” promoter is a promoter which is under environmental control.Examples of environmental conditions that may effect transcription byinducible promoters include anaerobic conditions or the presence oflight. Tissue-specific, tissue-preferred, cell type specific, andinducible promoters constitute the class of “non-constitutive”promoters. A “constitutive” promoter is a promoter which is active undermost environmental conditions.

A) Inducible Promoters

An inducible promoter is operably linked to a gene for expression insweet corn. Optionally, the inducible promoter is operably linked to anucleotide sequence encoding a signal sequence which is operably linkedto a gene for expression in sweet corn. With an inducible promoter therate of transcription increases in response to an inducing agent.

Any inducible promoter can be used in the instant invention. See Ward etal., Plant Mol. Biol. 22:361-366 (1993). Exemplary inducible promotersinclude, but are not limited to, that from the ACEI system whichresponds to copper (Mett et al., PNAS 90:4567-4571 (1993)); In2 genefrom maize which responds to benzenesulfonamide herbicide safeners (Gatzet al., Mol. Gen. Genetics 243:32-38 (1994)) or Tet repressor from Tn10(Gatz et al., Mol. Gen. Genetics 227:229-237 (1991)). A particularlypreferred inducible promoter is a promoter that responds to an inducingagent to which plants do not normally respond. An exemplary induciblepromoter is the inducible promoter from a steroid hormone gene, thetranscriptional activity of which is induced by a glucocorticosteroidhormone (Schena et al., Proc. Natl. Acad. Sci. U.S.A. 88:0421 (1991)).

B) Constitutive Promoters

A constitutive promoter is operably linked to a gene for expression insweet corn or the constitutive promoter is operably linked to anucleotide sequence encoding a signal sequence which is operably linkedto a gene for expression in sweet corn.

Many different constitutive promoters can be utilized in the instantinvention. Exemplary constitutive promoters include, but are not limitedto, the promoters from plant viruses such as the 35S promoter from CaMV(Odell et al., Nature 313:810-812 (1985)) and the promoters from suchgenes as rice actin (McElroy et al., Plant Cell 2:163-171 (1990));ubiquitin (Christensen et al., Plant Mol. Biol. 12:619-632 (1989) andChristensen et al., Plant Mol. Biol. 18:675-689 (1992)); pEMU (Last etal., Theor. Appl. Genet. 81:581-588 (1991)); MAS (Velten et al., EMBO J.3:2723-2730 (1984)) and maize H3 histone (Lepetit et al., Mol. Gen.Genetics 231:276-285 (1992) and Atanassova et al., Plant Journal 2 (3):291-300 (1992)). The ALS promoter, Xba1/Nco1 fragment 5′ to the Brassicanapus ALS3 structural gene (or a nucleotide sequence similarity to saidXba1/Nco1 fragment), represents a particularly useful constitutivepromoter. See PCT application WO96/30530.C.

C) Tissue-Specific or Tissue-Preferred Promoters

A tissue-specific promoter is operably linked to a gene for expressionin sweet corn. Optionally, the tissue-specific promoter is operablylinked to a nucleotide sequence encoding a signal sequence which isoperably linked to a gene for expression in sweet corn. Plantstransformed with a gene of interest operably linked to a tissue-specificpromoter produce the protein product of the transgene exclusively, orpreferentially, in a specific tissue.

Any tissue-specific or tissue-preferred promoter can be utilized in theinstant invention. Exemplary tissue-specific or tissue-preferredpromoters include, but are not limited to, a root-preferred promoter,such as that from the phaseolin gene (Murai et al., Science 23:476-482(1983) and Sengupta-Gopalan et al., Proc. Natl. Acad. Sci. U.S.A.82:3320-3324 (1985)); a leaf-specific and light-induced promoter such asthat from cab or rubisco (Simpson et al., EMBO J. 4(11):2723-2729 (1985)and Timko et al., Nature 318:579-582 (1985)); an anther-specificpromoter such as that from LAT52 (Twell et al., Mol. Gen. Genetics217:240-245 (1989)); a pollen-specific promoter such as that from Zm13or a microspore-preferred promoter such as that from apg (Twell et al.,Sex. Plant Reprod. 6:217-224 (1993)).

Signal Sequences for Targeting Proteins to Subcellular Compartments

Transport of protein produced by transgenes to a subcellular compartmentsuch as the chloroplast, vacuole, peroxisome, glyoxysome, cell wall ormitochondrion or for secretion into the apoplast, is accomplished bymeans of operably linking the nucleotide sequence encoding a signalsequence to the 5′ and/or 3′ region of a gene encoding the protein ofinterest. Targeting sequences at the 5′ and/or 3′ end of the structuralgene may determine, during protein synthesis and processing, where theencoded protein is ultimately compartmentalized.

The presence of a signal sequence directs a polypeptide to either anintracellular organelle or subcellular compartment or for secretion tothe apoplast. Many signal sequences are known in the art. See, forexample Becker et al., Plant Mol. Biol. 20:49 (1992), Knox, C., et al.,Plant Mol. Biol. 9:3-17 (1987), Lerner et al., Plant Physiol. 91:124-129(1989), Fontes et al., Plant Cell 3:483-496 (1991), Matsuoka et al.,Proc. Natl. Acad. Sci. 88:834 (1991), Gould et al., J. Cell. Biol.108:1657 (1989), Creissen et al., Plant 1 2:129 (1991), Kalderon, etal., Cell 39:499-509 (1984), Stiefel, et al., Plant Cell 2:785-793(1990).

Foreign Protein Genes and Agronomic Genes

With transgenic plants according to the present invention, a foreignprotein can be produced in commercial quantities. Thus, techniques forthe selection and propagation of transformed plants, which are wellunderstood in the art, yield a plurality of transgenic plants which areharvested in a conventional manner, and a foreign protein then can beextracted from a tissue of interest or from total biomass. Proteinextraction from plant biomass can be accomplished by known methods whichare discussed, for example, by Heney and Orr, Anal. Biochem. 114:92-6(1981).

According to a one embodiment, the transgenic plant provided forcommercial production of foreign protein is a sweet corn plant. Inanother preferred embodiment, the biomass of interest is seed or cob.For the relatively small number of transgenic plants that show higherlevels of expression, a genetic map can be generated, primarily viaconventional RFLP, PCR and SSR analysis, which identifies theapproximate chromosomal location of the integrated DNA molecule. Forexemplary methodologies in this regard, see Glick and Thompson, Methodsin Plant Molecular Biology and Biotechnology, Glick and Thompson Eds.,CRC Press, Boca Raton 269:284 (1993). Map information concerningchromosomal location is useful for proprietary protection of a subjecttransgenic plant. If unauthorized propagation is undertaken and crossesmade with other germplasm, the map of the integration region can becompared to similar maps for suspect plants, to determine if the latterhave a common parentage with the subject plant. Map comparisons wouldinvolve hybridizations, RFLP, PCR, SSR and sequencing, all of which areconventional techniques.

Likewise, by means of the present invention, agronomic genes can beexpressed in transformed plants. More particularly, plants can begenetically engineered to express various phenotypes of agronomicinterest. Exemplary genes implicated in this regard include, but are notlimited to, those categorized below:

Examples of Genes that Confer Resistance to Pests or Disease and thatEncode:

A. Plant disease resistance genes. Plant defenses are often activated byspecific interaction between the product of a disease resistance gene(R) in the plant and the product of a corresponding avirulence (Avr)gene in the pathogen. A plant variety can be transformed with one ormore cloned resistance gene to engineer plants that are resistant tospecific pathogen strains. See, for example Jones et al., Science266:789 (1994) (cloning of the tomato Cf-9 gene for resistance toCladosporium fulvum); Martin et al., Science 262:1432 (1993) (tomato Ptogene for resistance to Pseudomonas syringae pv. tomato encodes a proteinkinase); Mindrinos et al., Cell 78:1089 (1994) (Arabidopsis RSP2 genefor resistance to Pseudomonas syringae).

B. A Bacillus thuringiensis protein, a derivative thereof or a syntheticpolypeptide modeled thereon. See, for example, Geiser et al., Gene48:109 (1986), who disclose the cloning and nucleotide sequence of a Btalpha-endotoxin gene. Moreover, DNA molecules encoding alpha-endotoxingenes can be purchased from American Type Culture Collection, Manassas,Va., for example, under ATCC Accession Nos. 40098, 67136, 31995 and31998.

C. A lectin. See, for example, the disclosure by Van Damme et al., PlantMolec. Biol. 24:25 (1994), who disclose the nucleotide sequences ofseveral Clivia miniata mannose-binding lectin genes.

D. A vitamin-binding protein such as avidin. See PCT applicationUS93/06487. The application teaches the use of avidin and avidinhomologues as larvicides against insect pests.

E. An enzyme inhibitor, for example, a protease or proteinase inhibitoror an amylase inhibitor. See, for example, Abe et al., J. Biol. Chem.262:16793 (1987) (nucleotide sequence of rice cysteine proteinaseinhibitor), Huub et al., Plant Molec. Biol. 21:985 (1993) (nucleotidesequence of cDNA encoding tobacco proteinase inhibitor I), Sumitani etal., Biosci. Biotech. Biochem. 57:1243 (1993) (nucleotide sequence ofStreptomyces nitrosporeus alpha-amylase inhibitor).

F. An insect-specific hormone or pheromone such as an ecdysteroid andjuvenile hormone, a variant thereof, a mimetic based thereon, or anantagonist or agonist thereof. See, for example, the disclosure byHammock et al., Nature 344:458 (1990), of baculovirus expression ofcloned juvenile hormone esterase, an inactivator of juvenile hormone.

G. An insect-specific peptide or neuropeptide which, upon expression,disrupts the physiology of the affected pest. Pratt et al., Biochem.Biophys. Res. Comm. 163:1243 (1989) (an allostatin is identified inDiploptera puntata). See also U.S. Pat. No. 5,266,317 to Tomalski etal., who disclose genes encoding insect-specific, paralytic neurotoxins.

H. An insect-specific venom produced in nature by a snake, a wasp, etc.For example, see Pang et al., Gene 116:165 (1992), for disclosure ofheterologous expression in plants of a gene coding for a scorpioninsectotoxic peptide.

I. An enzyme responsible for a hyper-accumulation of a monoterpene, asesquiterpene, a steroid, a hydroxamic acid, a phenylpropanoidderivative or another non-protein molecule with insecticidal activity.

J. An enzyme involved in the modification, including thepost-translational modification, of a biologically active molecule; forexample, a glycolytic enzyme, a proteolytic enzyme, a lipolytic enzyme,a nuclease, a cyclase, a transaminase, an esterase, a hydrolase, aphosphatase, a kinase, a phosphorylase, a polymerase, an elastase, achitinase and a glucanase, whether natural or synthetic. See PCTapplication WO 93/02197 in the name of Scott et al., which discloses thenucleotide sequence of a callase gene. DNA molecules which containchitinase-encoding sequences can be obtained, for example, from the ATCCunder Accession Nos. 39637 and 67152. See also Kramer et al., InsectBiochem. Molec. Biol. 23:691 (1993), who teach the nucleotide sequenceof a cDNA encoding tobacco hornworm chitinase, and Kawalleck et al.,Plant Molec. Biol. 21:673 (1993), who provide the nucleotide sequence ofthe parsley ubi4-2 polyubiquitin gene.

K. A molecule that stimulates signal transduction. For example, see thedisclosure by Botella et al., Plant Molec. Biol. 24:757 (1994), ofnucleotide sequences for mung bean calmodulin cDNA clones, and Griess etal., Plant Physiol. 104:1467 (1994), who provide the nucleotide sequenceof a maize calmodulin cDNA clone.

L. A hydrophobic moment peptide. See PCT application WO95/16776(disclosure of peptide derivatives of Tachyplesin which inhibit fungalplant pathogens) and PCT application WO95/18855 (teaches syntheticantimicrobial peptides that confer disease resistance).

M. A membrane permease, a channel former or a channel blocker. Forexample, see the disclosure of Jaynes et al., Plant Sci. 89:43 (1993),of heterologous expression of a cecropin-beta, lytic peptide analog torender transgenic tobacco plants resistant to Pseudomonas solanacearum.

N. A viral-invasive protein or a complex toxin derived therefrom. Forexample, the accumulation of viral coat proteins in transformed plantcells imparts resistance to viral infection and/or disease developmenteffected by the virus from which the coat protein gene is derived, aswell as by related viruses. See Beachy et al., Ann. Rev. Phytopathol.28:451 (1990). Coat protein-mediated resistance has been conferred upontransformed plants against alfalfa mosaic virus, cucumber mosaic virus,tobacco streak virus, potato virus X, potato virus Y, tobacco etchvirus, tobacco rattle virus and tobacco mosaic virus.

O. An insect-specific antibody or an immunotoxin derived therefrom.Thus, an antibody targeted to a critical metabolic function in theinsect gut would inactivate an affected enzyme, killing the insect.

P. A virus-specific antibody. See, for example, Tavladoraki et al.,Nature 366:469 (1993), who show that transgenic plants expressingrecombinant antibody genes are protected from virus attack.

Q. A developmental-arrestive protein produced in nature by a pathogen ora parasite. Thus, fungal endo-alpha-1, 4-D-polygalacturonases facilitatefungal colonization and plant nutrient release by solubilizing plantcell wall homo-alpha-1, 4-D-galacturonase. See Lamb et al.,BioTechnology 10:1436 (1992). The cloning and characterization of a genewhich encodes a bean endopolygalacturonase-inhibiting protein isdescribed by Toubart et al., Plant J. 2:367 (1992).

R. A developmental-arrestive protein produced in nature by a plant. Forexample, Logemann et al., BioTechnology 10:305 (1992), have shown thattransgenic plants expressing the barley ribosome-inactivating gene havean increased resistance to fungal disease.

Genes that Confer Resistance to an Herbicide, for Example:

A. An herbicide that inhibits the growing point or meristem, such as animidazolinone or a sulfonylurea. Exemplary genes in this category codefor mutant ALS and AHAS enzyme as described, for example, by Lee et al.,EMBO J. 7:1241 (1988), and Miki et al., Theor. Appl. Genet. 80:449(1990), respectively.

B. Glyphosate (resistance conferred by mutant 5-enolpyruvlshikimate-3phosphate synthase (EPSP) and aroA genes, respectively) and otherphosphono compounds such as glufosinate (phosphinothricin acetyltransferase (PAT) and Streptomyces hygroscopicus PAT, bar, genes), andpyridinoxy or phenoxy propionic acids and cyclohexones (ACCaseinhibitor-encoding genes). See, for example, U.S. Pat. No. 4,940,835 toShah, et al., which discloses the nucleotide sequence of a form of EPSPwhich can confer glyphosate resistance. A DNA molecule encoding a mutantaroA gene can be obtained under ATCC accession number 39256, and thenucleotide sequence of the mutant gene is disclosed in U.S. Pat. No.4,769,061 to Comai. European patent application No. 0 333 033 to Kumadaet al., and U.S. Pat. No. 4,975,374 to Goodman et al., disclosenucleotide sequences of glutamine synthatase genes which conferresistance to herbicides such as L-phosphinothricin. The nucleotidesequence of a PAT gene is provided in European application No. 0 242 246to Leemans et al. DeGreef et al., BioTechnology 7:61 (1989), describethe production of transgenic plants that express chimeric bar genescoding for PAT activity. Exemplary of genes conferring resistance tophenoxy propionic acids and cyclohexones, such as sethoxydim andhaloxyfop are the Acc1-S1, Acc1-S2 and Acc1-S3 genes described byMarshall et al., Theor. Appl. Genet. 83:435 (1992).

C. An herbicide that inhibits photosynthesis, such as a triazine (psbAand gs+ genes) or a benzonitrile (nitrilase gene). Przibilla et al.,Plant Cell 3:169 (1991), describe the transformation of Chlamydomonaswith plasmids encoding mutant psbA genes. Nucleotide sequences fornitrilase genes are disclosed in U.S. Pat. No. 4,810,648 to Stalker, andDNA molecules containing these genes are available under ATCC AccessionNos. 53435, 67441, and 67442. Cloning and expression of DNA coding for aglutathione S-transferase is described by Hayes et al., Biochem. J.285:173 (1992).

Genes that Confer or Contribute to a Value-Added Trait, Such as:

A. Modified fatty acid metabolism, for example, by transforming a plantwith an antisense gene of stearyl-ACP desaturase to increase stearicacid content of the plant. See Knutzon et al., Proc. Natl. Acad. Sci.U.S.A. 89:2624 (1992)

B. Increased resistance to high light stress such as photo-oxidativedamages, for example by transforming a plant with a gene coding for aprotein of the Early Light Induced Protein family (ELIP) as described inWO 03/074713 in the name of Biogemma.

C. Modified carbohydrate composition effected, for example, bytransforming plants with a gene coding for an enzyme that alters thebranching pattern of starch. See Shiroza et al., J. Bact. 170:810 (1988)(nucleotide sequence of Streptococcus mutants fructosyltransferasegene), Steinmetz et al., Mol. Gen. Genet. 20:220 (1985) (nucleotidesequence of Bacillus subtilis levansucrase gene), Pen et al.,BioTechnology 10:292 (1992) (production of transgenic plants thatexpress Bacillus lichenifonnis .alpha.-amylase), Elliot et al., PlantMolec. Biol. 21:515 (1993) (nucleotide sequences of tomato invertasegenes), Sogaard et al., J. Biol. Chem. 268:22480 (1993) (site-directedmutagenesis of barley alpha-amylase gene), and Fisher et al., PlantPhysiol. 102:1045 (1993) (maize endosperm starch branching enzyme II).

D. Increased resistance/tolerance to water stress or drought, forexample, by transforming a plant to create a plant having a modifiedcontent in ABA-Water-Stress-Ripening-Induced proteins (ARS proteins) asdescribed in WO 01/83753 in the name of Biogemma, or by transforming aplant with a nucleotide sequence coding for a phosphoenolpyruvatecarboxylase as shown in WO 02/081714. The tolerance of corn to droughtcan also be increased by an overexpression of phosphoenolpyruvatecarboxylase (PEPC-C4), obtained, for example from sorghum.

E. Increased content of cysteine and glutathione, useful in theregulation of sulfur compounds and plant resistance against variousstresses such as drought, heat or cold, by transforming a plant with agene coding for an Adenosine 5′ Phosphosulfate as shown in WO 01/49855.

F. Increased nutritional quality, for example, by introducing a zeingene which genetic sequence has been modified so that its proteinsequence has an increase in lysine and proline. The increasednutritional quality can also be attained by introducing into the maizeplant an albumin 2S gene from sunflower that has been modified by theaddition of the KDEL peptide sequence to keep and accumulate the albuminprotein in the endoplasmic reticulum.

G. Decreased phytate content: 1) Introduction of a phytase-encoding genewould enhance breakdown of phytate, adding more free phosphate to thetransformed plant. For example, see Van Hartingsveldt et al., Gene127:87 (1993), for a disclosure of the nucleotide sequence of anAspergillus niger phytase gene. 2) A gene could be introduced thatreduced phytate content. In maize, this, for example, could beaccomplished, by cloning and then reintroducing DNA associated with thesingle allele which is responsible for maize mutants characterized bylow levels of phytic acid. See Raboy et al., Maydica 35:383 (1990).

Tissue Culture

As it is well known in the art, tissue culture of sweet corn can be usedfor the in vitro regeneration of sweet corn plants. Tissues cultures ofvarious tissues of sweet corn and regeneration of plants therefrom arewell known and published. By way of example, a tissue culture comprisingorgans has been used to produce regenerated plants as described inGirish-Chandel et al., Advances in Plant Sciences. 2000, 13: 1, 11-17,Costa et al., Plant Cell Report. 2000, 19: 3327-332, Plastira et al.,Acta Horticulturae. 1997, 447, 231-234, Zagorska et al., Plant CellReport. 1998, 17: 12 968-973, Asahura et al., Breeding Science. 1995,45: 455-459, Chen et al., Breeding Science. 1994, 44: 3, 257-262, Patilet al., Plant and Tissue and Organ Culture. 1994, 36: 2, 255-258. It isclear from the literature that the state of the art is such that thesemethods of obtaining plants are routinely used and have a very high rateof success. Thus, another aspect of this invention is to provide cellswhich upon growth and differentiation produce sweet corn plants havingthe physiological and morphological characteristics of sweet corn hybridplant HMX59B 5604.

As used herein, the term “tissue culture” indicates a compositioncomprising isolated cells of the same or a different type or acollection of such cells organized into parts of a plant. Exemplarytypes of tissue cultures are protoplasts, calli, plant clumps, and plantcells that can generate tissue culture that are intact in plants orparts of plants, such as embryos, pollen, flowers, seeds, leaves, stems,roots, root tips, anthers, pistils, meristematic cells, axillary buds,ovaries, seed coat, endosperm, hypocotyls, cotyledons and the like.Means for preparing and maintaining plant tissue culture are well knownin the art. By way of example, a tissue culture comprising organs hasbeen used to produce regenerated plants. U.S. Pat. Nos. 5,959,185,5,973,234, and 5,977,445 describe certain techniques, the disclosures ofwhich are incorporated herein by reference.

EXAMPLES

The foregoing examples of the related art and limitations relatedtherewith are intended to be illustrative and not exclusive. Otherlimitations of the related art will become apparent to those of skill inthe art upon a reading of the specification.

Example 1—Development of New HMX59BS604 Corn Variety

Breeding History:

Sweet corn hybrid plant HMX59BS604 has superior characteristics. Thefemale (361386) and male (SCM2) parents were crossed to produce hybrid(F1) seeds of HMX59BS604. The seeds of HMX59BS604 can be grown toproduce hybrid plants and parts thereof. The hybrid HMX59BS604 can bepropagated by seeds produced from crossing corn inbred line 361386 withcorn inbred line SCM2 or vegetatively.

The origin and breeding history of hybrid plant HMX59BS604 can besummarized as follows: the line 361386 also known internally to theapplicant as 235593-B (a line licensed by HM.CLAUSE, Inc.) was used asthe female plant and crossed by pollen from SCM2 (a proprietary lineowned by HM.CLAUSE, Inc.). The first trial planting of this hybrid wasdone in Stevens Point, Wis., in the summer of the first year. The hybridwas further trialed for two more years, an example of such trial beingdisclosed in Tables 2 and 3.

The inbred line 361386 is a white shrunken-2 inbred line used as thefemale parent in this cross. The inbred line 361386 has good performancein seed production, a well-proportioned ear, resistance to Pucciniasorghi (Rp1g) and a high level of eating quality.

The inbred line SCM2 is a yellow shrunken-2 inbred line used as the maleparent in this cross. The inbred line SCM2 has a strong plant type, darkgreen plant, husk leaves and flag leaves; maintains ear diameter as itmatures and has a high level of eating quality.

Sweet corn hybrid plant HMX59BS604 is similar to sweet corn hybrid plantSV7143. SV7143 is a commercial variety. While similar to sweet cornhybrid plant SV7143, there are significant differences including theplant height which is 76.1 inches for HMX59BS604 while SV7143 is 91.1inches, the fresh kernel width of HMX59BS604 is 8.4 mm while SV7143 is7.5 mm, the shank length of a husk ear of HMX59BS604 is 5.7 inches whilethe shank length of a husked ear of SV7143 is 3.7 inches. Also,HMX59BS604 sweet corn hybrids have a brix score of 15.7 while the brixscore of SV7143 is 14.6.

Some of the criteria used to select the hybrid HMX59BS604 and/or theirinbred parent lines in various generations include: strong, clean, darkgreen plant that resists root lodging, high field yield, long huskprotection, dark green husk leaves and attractive flag leaves,well-sized shipper ear, deep kernel, excellent kernel style andextremely high level of eating quality that holds well in the field, intransport and on the shelf.

The sweet corn hybrid plant HMX59BS604 has shown uniformity andstability for the traits, within the limits of environmental influencefor the traits as described in the following Variety DescriptiveInformation. No variant traits have been observed or are expected foragronomical important traits in sweet corn hybrid HMX59BS604.

Sweet corn hybrid plant HMX59BS604 has the following morphologic andother characteristics, as compared to SV7143 (based primarily on datacollected in Wisconsin, all experiments done under the directsupervision of the applicant).

TABLE 1 TRAIT DESCRIPTION TIMING HMX59BS604 SV7143 Check LOCATION SunPrairie, WI Sun Prairie, WI ROW NO. 16-45055 16-45067 TYPE Sweet,shrunken-2 Sweet, shrunken-2 (sh2) (sh2) COLOR Bicolor Bicolor Regionwhere developed in the USA Midwest Midwest Maturity in the Region ofBest Adaptability from planting to 50% of plants in silk Flowering 54 d56 d from planting to 50% of plants in pollen Flowering 53 d 54 d PlantTraits plant height to tassel tip (inches); average of Fresh 76.1 inches91.1 inches 10 plants harvest ear height to base of top ear node(inches); Fresh 23.3 inches 26.1 inches average of 10 plants harvestlength of top ear internode (inches); average Fresh 6.6 inches 6.9inches of 10 plants harvest anthocyanin of brace roots; absent, weak,Fresh absent absent medium, strong, very strong harvest Leaf Traitsfirst leaf: anthocyanin coloration of sheath; Emergence absent absentabsent, weak, medium, strong, very strong first leaf: shape of tip;pointed, pointed to Emergence pointed to rounded rounded rounded,rounded to spatulate, spatulate Foliage intensity of green color; light,Flowering medium medium medium, dark number of leaves above top ear;average of Flowering 4.5 6.2 10 plants width of ear node leaf (inches);average of 10 Fresh 3.8 inches 3.6 inches plants harvest length of earnode leaf (inches); average of Fresh 30.7 inches 31.6 inches 10 plantsharvest angle between blade and stem (on leaf just Flowering 3 3 aboveupper ear) 1-9 1 very small, 3 small +/= 25*, 5 med +/= 50*, 7 large +/=75*, 9 very large >= 90* leaf undulation of margin of blade (leaf aboveFlowering intermediate intermediate upper ear); absent, intermediate,strong degrees leaf angle on leaf just above upper Flowering moderatelymoderately ear (curvature) recurved recurved absent slight recurved modrecurved strongly recurved v strongly recurved sheath pubescence (1 =none to 9 = like Flowering 6 6 peach fuzz) leaf: anthocyanin colorationof sheath (in Flowering absent absent middle of plant) absent weakmedium strong very strong anthocyanin coloration of internodes (inFlowering absent absent middle of plant) absent weak medium strong verystrong stem: degree of zig-zag; absent, slight, strong Flowering slightslight Tassel Traits number of primary lateral branches; very few,Flowering 24.1 21.2 few, medium, many, very many branch angle fromcentral spike Flowering 5 5 1 very small, 3 small +/= 25*, 5 med +/=50*, 7 large +/= 75*, 9 very large >= 90* angle between main axis andlateral branches Flowering 3 5 (in lower third of tassel) 1 very small,3 small +/= 25*, 5 med+/= 50*, 7 large +/= 75*, 9 very large >= 90*attitude (curvature) of lateral branches, in Flowering absent absentlower third of tassel absent slight recurved mod recurved stronglyrecurved v strongly recurved Length of lateral branches, in lower thirdof Flowering 9.4 inches 8.6 inches tassel (inches) length from top leafcollar to tassel tip Fresh 17.2 inches 17.3 inches (inches); average of10 plants harvest length above lowest lateral branch (inches); Flowering15.8 inches 15.4 inches average of 10 plants length above highestlateral branch (inches); Flowering 9 inches 9 inches average of 10plants anther color; yellow, green, red, pink Flowering yellow yellowglume color; green, red Flowering green green bar glumes (glume bands);absent, present Flowering absent absent Anthocyanin coloration at baseof glumes; Flowering absent absent absent, weak, medium, strong, verystrong Anthocyanin coloration of glumes (middle Flowering absent absentthird main branch); absent, weak, medium, strong, very strongAnthocyanin coloration of anthers (middle Flowering absent absent third,fresh anthers) absent weak medium strong very strong Silk: intensity ofanthocyanin coloration of Flowering absent absent silks; absent, weak,medium, strong, very strong Silk: intensity of anthocyanin coloration ofFlowering absent absent silks; absent, weak, medium, strong, very strongEar Traits silk color (3 days after emergence); yellow, Flowering yellowyellow green, pink, red (unhusked data) husk tightness (1 = very looseto 9 = very Fresh 7 7 tight) (unhusked data) harvest husk extension (atharvest) in inches Fresh 1.9 inches 1.7 inches (unhusked data) harvestear length; average of 10 ears (husked ear Fresh 20.3 cm 20.9 cm data)harvest ear diameter at mid-point, average of 10 ears Fresh 4.9 cm 4.6cm (husked ear data) harvest number of kernel rows, average of 10 earsFresh 18 18 (husked ear data) harvest row alignment (1 to 9), average of10 ears Fresh 4 4 (husked ear data) harvest shank length in inches,average of 10 ears Fresh 5.7 inches 3.7 inches (husked ear data) harvestear taper; conical, conical cylindrical, Fresh conical conicalcylindrical, average of 10 ears (husked ear harvest cylindricalcylindrical data) number of kernel colors; one or two Fresh two twoharvest intensity of yellow color; light, medium, Fresh medium mediumdark, average of 10 ears harvest fresh kernel width (mm), average of 10ears Fresh 8.4 mm 7.5 mm harvest fresh kernel depth (mm), average of 10ears Fresh 10.1 mm 10.6 mm harvest endosperm type; sh2 or su1 PrePlanting sh2 sh2 eating quality; excellent, good, fair, poor Freshgood-excellent harvest brix; average of 10 ears Fresh 15.7 14.6 harvestCob Traits diameter at mid-point (cm); average of 10 Fresh 2.8 cm 2.6 cmears harvest cob color Fresh white white harvest Disease Reaction TraitsCommon Rust (Puccinia sorghi) Fresh HR (Rp1-g) HR (Rp1-dg) harvest MaizeDwarf Mosaic Virus (MDMV) Fresh harvest Stewart's Bacterial Wilt(Pantoea stewartii) Fresh IR harvest Northern Corn Leaf Blight Fresh IR(Exserohilum turcicum) harvest Notes; market niche Fresh US/SE, NE, MW,US/SE, NE, MW, harvest CA CA

Example 2—Field Trials Characteristics of Hybrid Corn Plant HMX59BS604

In Tables 2 through 5, the traits and characteristics of hybrid sweetcorn plant HMX59BS604 are compared to the variety SV7143. The data wascollected during two growing season from several field locations in theUnited States, all experiments done under the direct supervision of theapplicant.

In Tables 2 and 3, the first column shows the variety name, the secondcolumn shows the location and year of testing. The third column “PLTRATE” is the overall rating of the plants in the plot, on a 1 to 9 scalewhere 1 is for weak plants, plants with tilled and/or lodged plants,while 9 is for strong plants, uniform, with few tillers and standing.The fourth column “MRK EARS” is the number of marketable ears per plots,on a 1 to 9 scale where 1 is for plants with few marketable ears inplots and 9 is for plants with high number of marketable ears in plots.The fifth column “SNAP” is the ear removal from stalks, on a 1 to 9scale where 1 is for plants when it is difficult to pull ear from stalk,while 9 is for an easy removal of the ear from stalk. The sixth column“HSK CLR” is the husk leaf color on a 1 to 9 scale where 1 is for pale,light green or yellow husk leaves while 9 is for uniform dark green huskleaves. The seventh column “FLAGS” is for the appearance of flag leaveson a 1 to 9 scale where 1 is no or few short flag leaves and 9 is a highnumber of flag leaves, with a good length and uniform dark green color.The eight column “HUSK P” is the husk protection of ear tip, on a 1 to 9scale, where 1 is when the ear is exposed for 2 inches or more and 9 iswhen husk is extending beyond the ear tip by 3.5 inches and the hush aretightly wrapped.

TABLE 2 TRIAL PLT MRK HSK VARIETY LOCATION RATE EARS SNAP CLR FLAGS HUSKP HMX59BS604 Stevens 7 7 6 7 7 7 Point, WI Year 2 SV7143SC Stevens 6 7 75 5 5 Point, WI Year 2

TABLE 3 TRIAL PLT MRK HSK VARIETY LOCATION RATE EARS SNAP CLR FLAGS HUSKP HMX59BS604 Stevens 7 6 6 6 6 6 Point, WI Year 1 SV7143SC Stevens 7 6 55 5 5 Point, WI Year 1In table 4 and 5, the first column shows the variety name, the secondcolumn shows the location of testing. The third column “TIP FILL” is thekernel fill to tip of the ear, on a 1 to 9 scale where 1 is for up to 3inches blanking, while 9 is for completely filled ear tip. The fourthcolumn “K STYLE” is the relative size or style of kernel, on a 1 to 9scale, where 1 is for very large, blocky rounded kernels and 9 is forsmall refined, even kernels. The fifth column “K COLOR” is the kernelcolor for yellow or white sweet corn, on a 1 to 9 scale where 1 is fordull, pale, or uneven kernel color while 9 is for kernels with anuniform, intense color, with a glossy appearance. The sixth column “KCC”is for the kernel color contrast for bicolor sweet corn, on a 1 to 9scale where 1 is poor contrast, pale, dull, washed poor colors and 9 isfor kernels having a high level of contrast, bright, with glossy intensecolors. The seventh column “TENDER” is the tenderness of pericarp or theease of bite, on a 1 to 9 scale, where 1 is for tough, firm pericarp and9 is for very tender pericarp, without splitting in the field. The eightcolumn “SWEET” is for the intensity of kernel sweetness when eaten, on a1 to 9 scale, where 1 is for bland and objectionable taste while 9 isfor intensively sweet, favorable kernels.

TABLE 4 TRIAL TIP K K VARIETY LOCATION FILL STYLE COLOR KCC TENDER SWEETHMX59BS604 Stevens 7 7 6 6 7 7 Point, WI Year 2 SV7143SC Stevens 6 6 7 66 6 Point, WI Year 2

TABLE 5 TRIAL TIP K K VARIETY LOCATION FILL STYLE COLOR KCC TENDER SWEETHMX59BS604 Stevens 7 6 7 7 7 6 Point, WI Year 1 SV7143SC Stevens 6 7 7 75 6 Point, WI Year 1

DEPOSIT INFORMATION

A deposit of the sweet corn seed of this invention is maintained byHM.CLAUSE, Inc. HM.CLAUSE, Sun Prairie Research & Development, 1677Muller Road, Sun Prairie, Wis. 53590 USA. In addition, a sample of thesweet corn hybrid seed of this invention has been deposited with theNational Collections of Industrial, Food and Marine Bacteria (NCIMB), 23St Machar Drive, Aberdeen, Scotland, AB24 3RY, United Kingdom.

To satisfy the enablement requirements of 35 U.S.C. 112, and to certifythat the deposit of the isolated strain of the present invention meetsthe criteria set forth in 37 CFR 1.801-1.809, Applicants hereby make thefollowing statements regarding the deposited sweet corn hybridHMX59BS604 (deposited as NCIMB Accession No. 43394):

1. During the pendency of this application, access to the invention willbe afforded to the Commissioner upon request;

2. All restrictions on availability to the public will be irrevocablyremoved upon granting of the patent under conditions specified in 37 CFR1.808;

3. The deposit will be maintained in a public repository for a period of30 years or 5 years after the last request or for the effective life ofthe patent, whichever is longer;

4. A test of the viability of the biological material at the time ofdeposit will be conducted by the public depository under 37 CFR 1.807;and

5. The deposit will be replaced if it should ever become unavailable.

Access to this deposit will be available during the pendency of thisapplication to persons determined by the Commissioner of Patents andTrademarks to be entitled thereto under 37 C.F.R. § 1.14 and 35 U.S.C. §122. Upon allowance of any claims in this application, all restrictionson the availability to the public of the variety will be irrevocablyremoved by affording access to a deposit of at least 2,500 seeds of thesame variety with the NCIMB.

INCORPORATION BY REFERENCE

All references, articles, publications, patents, patent publications,and patent applications cited herein are incorporated by reference intheir entireties for all purposes.

However, mention of any reference, article, publication, patent, patentpublication, and patent application cited herein is not, and should notbe taken as an acknowledgment or any form of suggestion that theyconstitute valid prior art or form part of the common general knowledgein any country in the world.

What is claimed is:
 1. A seed of sweet corn hybrid designatedHMX59BS604, wherein a representative sample of seed of said hybrid hasbeen deposited under NCIMB No.
 43394. 2. A sweet corn plant, a plantpart thereof, or a plant cell thereof, produced by growing the seed ofclaim 1, wherein a sweet corn plant regenerated from said plant part orplant cell has all of the physiological and morphologicalcharacteristics of hybrid HMX59BS604 listed in Table 1 when grown underthe same environmental conditions.
 3. The sweet corn plant part, or aplant cell thereof of claim 2, wherein the sweet corn part is selectedfrom the group consisting of a leaf, a flower, an ear, a cell, arootstock, and a scion.
 4. A sweet corn plant or a plant part, or aplant cell thereof having all of the physiological and morphologicalcharacteristics of hybrid HMX59BS604 listed in Table 1 when grown underthe same environmental conditions, wherein a representative sample ofseed of said hybrid has been deposited under NCIMB No.
 43394. 5. Atissue culture of regenerable cells produced from the plant or plantpart of claim 2, wherein a plant regenerated from the tissue culture hasall of the physiological and morphological characteristics of hybridHMX59BS604 listed in Table 1 when grown in the same environmentalconditions.
 6. A sweet corn plant regenerated from the tissue culture ofclaim 5, said plant having all of the physiological and morphologicalcharacteristics of hybrid HMX59BS604, listed in Table 1 when grown underthe same environmental conditions, wherein a representative sample ofseed of said hybrid has been deposited under NCIMB No.
 43394. 7. A sweetcorn ear produced from the plant of claim
 2. 8. A method for harvestinga sweet corn ear comprising a) growing the sweet corn plant of claim 2to produce a sweet corn ear, and b) harvesting said sweet corn ear.
 9. Asweet corn ear produced by the method of claim
 8. 10. A method forproducing a sweet corn seed comprising crossing a first parent sweetcorn plant with a second parent sweet corn plant and harvesting theresultant sweet corn seed, wherein said first parent sweet corn plantand/or second parent sweet corn plant is the sweet corn plant of claim2.
 11. A method for producing a sweet corn seed comprisingself-pollinating the sweet corn plant of claim 2 and harvesting theresultant sweet corn seed.
 12. A method of vegetatively propagating thesweet corn plant of claim 2, said method comprising a) collecting partof a plant of claim 2 and b) regenerating a plant from said part. 13.The method of claim 12 further comprising harvesting an ear from saidplant.
 14. A plant obtained from the method of claim 13, wherein saidplant has all of the physiological and morphological characteristics ofhybrid HMX59BS604 listed in Table 1 when grown under the sameenvironmental conditions.
 15. An ear obtained from the method of claim13, wherein plans grown from the kernels of the ear exhibit all of thephysiological and morphological characteristics of sweet corn hybridHMX59BS604 listed in Table
 1. 16. A method of producing a sweet cornplant derived from the hybrid variety HMX59BS604, the method comprising:(a) self-pollinating the plant of claim 2 at least once to produce aprogeny plant derived from the hybrid variety HMX59BS604.
 17. The methodof claim 16 further comprising the steps of: (b) crossing the progenyplant derived from the sweet corn hybrid HMX59BS604 with itself or asecond corn plant to produce a seed of progeny plant of subsequentgeneration; (c) growing the progeny plant of the subsequent generationfrom the seed; (d) crossing the progeny plant of the subsequentgeneration with itself or a second sweet corn plant to produce a sweetcorn plant derived from the sweet corn hybrid variety HMX59BS604; and(e) repeating step b) and/or c) for at least one generation to produce asweet corn plant derived from the sweet corn hybrid HMX59BS604.
 18. Amethod of producing a sweet corn plant derived from the sweet cornhybrid HMX59BS604, the method comprising; (a) crossing the plant ofclaim 2 with a second corn plant to produce a progeny plant.
 19. Themethod of claim 18 further comprising the steps of: (b) crossing theprogeny plant derived from the variety HMX59BS604 with itself or asecond corn plant to produce a seed of progeny plant of subsequentgeneration; (c) growing the progeny plant of the subsequent generationfrom the seed; (d) crossing the progeny plant of the subsequentgeneration with itself or a second sweet corn plant to produce a sweetcorn plant derived from the sweet corn hybrid HMX59BS604; and (e)repeating step b) and/or c) to produce a sweet corn plant derived fromthe sweet corn hybrid HMX59BS604.
 20. The plant of claim 2 wherein saidplant further comprises at least one single locus conversion andotherwise comprising all of the physiological and morphologicalcharacteristics of sweet corn hybrid HMX59BS604 listed in Table 1 whengrown under the same environmental conditions.
 21. The plant of claim 20wherein the single locus conversion confers said plant with herbicideresistance.
 22. The plant of claim 20, wherein the single locusconversion is an artificially mutated gene or nucleotide sequence. 23.The plant of claim 20 wherein the single locus conversion is a gene thathas been modified through the use of a New Breeding Technique.
 24. Amethod for producing nucleic acids, the method comprising isolatingnucleic acids from the plant of claim 2, or a plant part, or a plantcell thereof.
 25. A method for producing a second sweet corn plant, themethod comprising applying plant breeding techniques to the plant orplant part of claim 2 to produce the second sweet corn plant.
 26. Amethod for producing a transgenic sweet corn plant, the methodcomprising crossing the sweet corn plant of claim 2 with a second cornplant containing a transgene, wherein the transgene of said second cornplant is integrated into the genome of the sweet corn plant progenyresulting from said cross.
 27. The plant of claim 2, wherein said plantfurther comprises a transgene.